Friday, December 8, 2023

💥💥💥 What is FEATool and what is used for ?

FEAtool is a fully integrated simulation platform that allows you to model and simulate coupled physics phenomena, partial differential equations, continuum mechanics, and engineering problems. It offers a customizable and extensible GUI, reproducible simulation results, and one-click export to various formats.

FEAtool can work with different solvers such as OpenFOAM, SU2, and FEniCS. It also supports MATLAB® scripting and toolboxes for optimization and control systems. You can use FEAtool to set up, define, export, and run multiphysics mesh and case files for your simulation needs.

FEAtool is used for a wide range of applications, such as fluid flow, heat transfer, structural mechanics, electromagnetics, acoustics, and more. You can use FEAtool to solve complex engineering problems, design and optimize products, or conduct research and education.

If you want to learn more about how to use FEAtool, you can check out the documentation , the tutorials , or the community forum where you can find more information and support from other users.

How much does FEAtool cost?

FEAtool pricing depends on the license type, the duration, and the technical support option. The license types are personal/hobby, academic/research, and commercial/enterprise. The duration can be either 1 year or perpetual (non-expiring). The technical support can be either community support (public forum) or dedicated developer support1

The web search results also show some examples of FEAtool pricing from different sources. For instance, one source 2 says that the starting price for FEAtool is $203.63 per year, while another source 3 says that the price for FEAtool is $4995.00.

However, these prices may not reflect the current or accurate pricing of FEAtool, as they are based on limited or outdated information. Therefore, I suggest you to contact the official FEAtool website or use their contact form to get more information about their pricing and licensing options.

Can I get FEATool for free?

FEAtool is not available for free, but it has different pricing and licensing options depending on your needs and budget. You can choose between personal/hobby, academic/research, and commercial/enterprise license types, and between 1 year or perpetual (non-expiring) duration. You can also choose between community support (public forum) or dedicated developer support1

However, you can also request a quote or a trial license if you want to try FEAtool before buying it. You can contact the official FEAtool website or use their contact form to get more information about their pricing and licensing options1

What are capabilities of FEATool ?

Can I use FEATool for structural analysis?

Yes, you can use FEATool for structural analysis. FEATool is a software platform for finite element analysis and computational fluid dynamics that supports various physics modes, including structural mechanics1

With FEATool, you can model and simulate objects and structures under varying load conditions, such as forces, pressures, temperatures, and displacements. You can also analyze the resulting stresses, strains, deformations, and failure modes12

FEATool has a library of tutorial models and examples for structural mechanics, such as thin plate with hole, cantilever beam, cylindrical pressure vessel, heat induced stress in a brake disc, and fluid-structure interaction. You can access these models from the File > Model Examples and Tutorials menu or from the documentation3

Are OpenFoam and Fenics solvers automatically installed with FEATool?

OpenFOAM and FEniCS solvers are not automatically installed with FEATool, as every system and OS needs specific versions for compatibility. They must be installed separately before using them with FEATool12

You can find the installation instructions for OpenFOAM and FEniCS solvers on their official websites or in the FEATool documentation12

Once you have installed the solvers, you can use them with FEATool by selecting the appropriate solver settings and control panel in the Solve Mode. You can also export and run simulations as MATLAB scripts, or use FEATool as a pre and post-processor for the solvers123

I hope this helps you with your project. If you have any other questions, feel free to ask me. 😊

Tuesday, December 5, 2023

💥💥💥 What is Open Modelica and what is used for?

 Open Modelica is a free and open source environment for modeling, simulating, optimizing and analyzing complex dynamic systems using the Modelica language¹. Modelica is a declarative, object-oriented language for modeling physical systems that can involve multiple domains such as mechanical, electrical, thermal, fluid, and control².

Open Modelica is used for industrial and academic purposes, such as engineering design, research, education, and training. It provides various tools and applications, such as:

- OMC: The OpenModelica Compiler, which translates Modelica code into executable code and supports the Functional Mockup Interface (FMI) standard for model exchange and co-simulation¹.

- OMEdit: The OpenModelica graphical user interface, which allows users to create, edit, simulate, and debug Modelica models using a graphical or textual editor¹.

- OMShell: The OpenModelica command-line interface, which allows users to interact with the OMC and perform various operations on Modelica models¹.

- OMNotebook: The OpenModelica interactive notebook, which allows users to combine Modelica code, documentation, and simulation results in a single document¹.

- OMPython: The OpenModelica Python interface, which allows users to access the OMC from Python scripts and use Python libraries for data analysis and visualization¹.

- OMMatlab: The OpenModelica Matlab interface, which allows users to access the OMC from Matlab and use Matlab functions and toolboxes for data analysis and visualization¹.

You can learn more about Open Modelica and its features, tools, applications, and how to join the project and contribute by visiting their official website¹ or their Wikipedia page³. 

Source: 

(1) OPENMODELICA. https://openmodelica.org/.

(2) Download Windows - OPENMODELICA. https://openmodelica.org/download/download-windows/.

(3) OpenModelica - Wikipedia. https://en.wikipedia.org/wiki/Openmodelica.

What is the difference between Modelica and Simulink?

The difference between Modelica and Simulink is that they use different approaches to model and simulate physical systems. Modelica uses an equation-based or acausal approach, while Simulink uses a signal flow-based or causal approach¹.

In an equation-based or acausal approach, the components are connected by physical connectors that represent physical quantities such as force, voltage, or temperature. The components do not have fixed inputs and outputs, but rather define equations that describe the relationship between the physical quantities. The direction of the information flow is not predefined, but determined by the solver that solves the system of equations. This allows for more flexibility and modularity in modeling complex systems that involve multiple domains and feedback loops².

In a signal flow-based or causal approach, the components are connected by signals that represent data values such as numbers, vectors, or matrices. The components have fixed inputs and outputs, and compute the outputs from the inputs by explicit assignments and operations. The direction of the information flow is predefined and cannot be changed. This requires the user to specify how the signals interact with each other and how to handle algebraic loops and discontinuities³.

Both approaches have their advantages and disadvantages, depending on the type and complexity of the system to be modeled and simulated. Some of the advantages of Modelica over Simulink are:

- Modelica is an open-source and standardized language that can be used in various simulation environments, while Simulink is a proprietary and platform-dependent tool that requires Matlab.

- Modelica allows for more natural and intuitive modeling of physical systems, as it does not require the user to define the causality and direction of the information flow.

- Modelica supports object-oriented and hierarchical modeling, which enables reuse and inheritance of components and models.

- Modelica supports the Functional Mockup Interface (FMI) standard, which enables model exchange and co-simulation with other tools that support FMI.


Some of the advantages of Simulink over Modelica are:

- Simulink is more mature and widely used in the industry and academia, and has a large user community and support network.

- Simulink has a user-friendly and graphical interface, and integrates well with Matlab and other MathWorks products.

- Simulink offers a range of solutions and toolboxes for different applications and domains, such as control design, signal processing, embedded systems, and machine learning.

- Simulink has more advanced and robust solvers and algorithms, and supports code generation and hardware-in-the-loop testing.

Source: 

(1) Modelica vs Simulink - TLK Energy. https://tlk-energy.de/blog-en/modelica-vs-simulink.

(2) Compare Modelica vs. Simulink | G2. https://www.g2.com/compare/modelica-vs-simulink.

(3) Matlab Simscape vs Simulink vs PDE-Toolbox/Ansys/Comsol. https://stackoverflow.com/questions/56992867/matlab-simscape-vs-simulink-vs-pde-toolbox-ansys-comsol.

Can I model Conjugate Heat Transfer in Open Modelica?

Yes, you can model conjugate heat transfer in Open Modelica, which is the process of heat transfer between a solid and a fluid in contact with each other. To do so, you need to use the components from the Modelica.Thermal.HeatTransfer library, which contains models for 1-dimensional heat transfer with lumped elements¹. You can also use the components from the Buildings.HeatTransfer.Convection library, which contains models for convective heat transfer between a solid and a fluid².

For example, you can use the ThermalConductor component to model the heat conduction in the solid, the ConvectiveHeatTransfer component to model the heat transfer coefficient between the solid and the fluid, and the HeatCapacitor component to model the heat capacity of the solid and the fluid. You can also use the FixedTemperature component to model the boundary conditions of the solid and the fluid, such as the inlet and outlet temperatures¹.

You can find some example models that demonstrate the usage of these components in the Modelica.Thermal.HeatTransfer.Examples package³. For instance, the Motor example shows how to model the heating of an electrical motor, which involves conjugate heat transfer between the winding, the core, and the air³. You can also check out this question on Stack Overflow that shows how to model the convective heat transfer of the fluid inside a dynamic pipe⁴.

Source: 

(1) Modelica.Thermal.HeatTransfer.UsersGuide. https://doc.modelica.org/Modelica%204.0.0/Resources/helpDymola/Modelica_Thermal_HeatTransfer_UsersGuide.html.

(2) Buildings.HeatTransfer.Convection. https://simulationresearch.lbl.gov/modelica/releases/v9.1.0/help/Buildings_HeatTransfer_Convection.html.

(3) Modelica.Thermal.HeatTransfer.Examples - Maplesoft. https://www.maplesoft.com/documentation_center/online_manuals/modelica/Modelica_Thermal_HeatTransfer_Examples.html.

(4) Question about convection heat transfer in the dynamic pipe of the .... https://stackoverflow.com/questions/71123874/question-about-convection-heat-transfer-in-the-dynamic-pipe-of-the-modelica-stan.


💥💥💥 Examples of FEA software that can create FMU files

 FEA programs that can create FMU files are software packages that implement the finite element method for solving partial differential equations and can export their models as functional mockup units (FMUs) for co-simulation or model exchange. FMUs are standardized files that contain a description of the model, its variables, and its equations, as well as one or more platform-dependent shared libraries that implement the model behavior³. FMUs can be used to simulate complex systems that involve multiple components and subsystems⁴.

Some examples of FEA programs that can create FMU files are:

- Simulink Compiler™ FMU Builder for Simulink Support Package: This is a tool that allows you to export Simulink models to FMUs that support co-simulation in FMI version 2.0 and 3.0¹. Simulink is a graphical programming environment for modeling, simulating, and analyzing multidomain systems.

- pythonfmu: This is a lightweight framework that enables the packaging of Python3.x code as co-simulation FMUs³. Python is a popular and versatile programming language that can be used for scientific computing, data analysis, machine learning, and more.

- GOMA: This is an open-source, parallel, and scalable multiphysics software package for modeling and simulation of real-life physical processes, with a basis in computational fluid dynamics for problems with evolving geometry. It can export FMUs for FMI 2.0².

- OpenModelica: This is an open-source, standards-compliant, Modelica-based modeling and simulation environment. It can export FMUs for FMI 1.0 and 2.0. Modelica is a declarative, object-oriented language for modeling complex physical systems.

- Dymola: This is a commercial modeling and simulation tool based on the Modelica language. It can export FMUs for FMI 1.0, 2.0, and 3.0.

- ANSYS Twin Builder: This is a platform for building, validating, and deploying digital twins. It can import and export FMUs for FMI 2.0 and 3.0. A digital twin is a virtual representation of a physical system that can be used for testing, optimization, and prediction.

If you want to learn more about FEA programs that can create FMU files, you can check out this list of finite element software packages² or this article that explains what is a FMU⁴. I hope this helps you to understand more about FEA programs that can create FMU files. 😊.

Source: 

(1) .FMU File Extension - How do I open it? - WhatExt. https://whatext.com/fmu.

(2) Functional Mockup Unit (FMU) Explained - Collimator. https://www.collimator.ai/reference-guides/what-is-a-fmu.

(3) 4. Creating an FMU — FMU Export of EnergyPlus User Guide. https://simulationresearch.lbl.gov/fmu/EnergyPlus/export/userGuide/build.html.

(4) List of finite element software packages - Wikipedia. https://en.wikipedia.org/wiki/List_of_finite_element_software_packages.

How do I use FMUs for simulation?

To use FMUs for simulation, you need to have a simulation tool that supports the Functional Mockup Interface (FMI) standard, which defines how FMUs can be imported and exported across different simulation environments. Some examples of simulation tools that support FMI are Simulink, OpenModelica, Dymola, and ANSYS Twin Builder¹.

Depending on the type of FMU you have, you can use different methods to simulate it. There are two types of FMUs: Model Exchange (ME) and Co-Simulation (CS). In an ME FMU, the model is solved inside the FMU, with the simulation tool acting only as the solver. In a CS FMU, the model is solved by the simulation tool and the FMU, which communicate with each other through a shared data structure².

To simulate an ME FMU, you need to connect the FMU to a numerical solver that can set the FMU state, ask for the state derivatives, determine an appropriate step size, and decide how to compute the state at the next time step³. To simulate a CS FMU, you need to specify the communication step size between the simulation tool and the FMU, which determines how often they exchange data⁴.

For example, if you want to simulate an ME FMU using Simulink, you can use the FMU Import block to load the FMU file into your model. The block automatically selects the ME mode and connects the FMU to the Simulink solver. You can then run the simulation and observe the results¹.

If you want to simulate a CS FMU using PyFMI, you can use the load_fmu function to load the FMU file into a Python script. The function automatically selects the CS mode and creates an FMUModelCS object. You can then use the simulate method to run the simulation and return the results⁴.

Source:

(1) Include Functional Mockup Unit (FMU) in model - Simulink - MathWorks. https://www.mathworks.com/help/simulink/ref_extras/fmu.html.

(2) Functional Mockup Unit (FMU) Explained - Collimator. https://www.collimator.ai/reference-guides/what-is-a-fmu.

(3) FMI, FMU, and Bonsai - Bonsai | Microsoft Learn. https://learn.microsoft.com/en-us/bonsai/concepts/fmu/.

(4) Tutorial — PyFMI 2.5 documentation - Modelica. https://jmodelica.org/pyfmi/tutorial.html.

What is the difference between co-simulation and model exchange?

Co-simulation and model exchange are two types of protocols for using functional mockup units (FMUs) in simulation. FMUs are standardized files that contain a description of a model, its variables, and its equations, as well as one or more platform-dependent shared libraries that implement the model behavior¹.

The main difference between co-simulation and model exchange is that in co-simulation, the FMU is shipped with its own solver, while in model exchange, the FMU is simulated using the importing tool's solver². This means that in co-simulation, the FMU and the importing tool communicate with each other through a shared data structure at discrete time steps, while in model exchange, the importing tool sets the FMU state, asks for the state derivatives, and decides how to compute the state at the next time step³.

Co-simulation is suitable for models that require specialized solvers or have complex dynamics that are difficult to integrate with other models. Co-simulation also allows for parallel execution of multiple FMUs on different processors or machines. However, co-simulation requires the user to specify the communication step size between the FMU and the importing tool, which can affect the accuracy and performance of the simulation⁴.

Model exchange is suitable for models that do not require specialized solvers or have simple dynamics that are easy to integrate with other models. Model exchange also allows for better control and flexibility over the simulation process, as the importing tool can choose the most appropriate solver and step size for the FMU. However, model exchange requires the importing tool to support the Functional Mockup Interface (FMI) standard and be able to handle the FMU equations⁵.

Source: 

(1) FMI basics Co-simulation vs. Model Exchange - Claytex. https://www.claytex.com/tech-blog/fmi-basics-co-simulation-vs-model-exchange/.

(2) FMI Standard: Co-Simulation vs. Model Exchange FMUs. https://modelon.com/blog/fmi-functional-mock-up-unit-types/.

(3) Functional Mock-up Interface - Wolfram. https://reference.wolfram.com/system-modeler/UserGuide/ModelCenterFunctionalMockupInterface.html.

(4) Co-simulation - Open Simulation Platform. https://opensimulationplatform.com/co-simulation/.

(5) Introduction to FMI - Claytex. https://www.claytex.com/blog/introduction-to-fmi/.

Monday, December 4, 2023

💥💥💥 What models are available in PyTorch for machine learning based on residual (incomplete) data?

PyTorch is a popular open-source framework for deep learning that provides a flexible and modular way to build and train neural network models. PyTorch offers many models for various tasks, such as computer vision, natural language processing, generative modeling, and reinforcement learning. Some of these models are available in the official PyTorch Vision and PyTorch Text libraries, while others can be found in third-party repositories or online tutorials.

One of the challenges of machine learning is dealing with incomplete or missing data, which can affect the performance and accuracy of the models. There are different ways to handle this problem, such as imputing the missing values, using masking techniques, or applying regularization methods. However, some models are inherently more robust to incomplete data than others, because they can learn from the residual information in the data.


One example of such models is ResNet, which stands for Residual Network. ResNet is a type of convolutional neural network (CNN) that uses skip connections or shortcuts to bypass some layers and create residual blocks. This way, the network can learn the identity function when the layers are not needed, and avoid the problem of vanishing or exploding gradients. ResNet can also handle incomplete data better than other CNNs, because it can learn from the residual features that are not affected by the missing values. ResNet was originally proposed for image recognition in the paper Deep Residual Learning for Image Recognition, and it has since been applied to various domains and tasks. ResNet is available in PyTorch Vision, and you can find the documentation and examples here.

Another example of models that can handle incomplete data is Transformers, which are a type of neural network that use attention mechanisms to learn the dependencies and relationships between the input and output sequences. Transformers can deal with incomplete data by using masking techniques, such as masking some tokens in the input or output sequences and predicting them based on the context. Transformers can also use positional encoding to capture the order and position of the tokens, which can be useful when some tokens are missing. Transformers were originally proposed for natural language processing in the paper Attention Is All You Need, and they have since been extended and adapted to various domains and tasks. Transformers are available in PyTorch Text, and you can find the documentation and examples [here].

Some more examples of models in PyTorch that can operate on residual data are:

  • DenseNet - DenseNet is a type of convolutional neural network that uses dense connections between layers, meaning that each layer receives input from all previous layers and passes its output to all subsequent layers. This way, the network can reuse features and learn from the residual information in the data. DenseNet was proposed for image classification in the paper Densely Connected Convolutional Networks, and it has since been applied to various domains and tasks. DenseNet is available in PyTorch Vision, and you can find the documentation and examples here.
  • BERT - BERT is a type of Transformer model that uses bidirectional attention to learn the context and meaning of natural language. BERT can handle incomplete data by using masking techniques, such as masking some words in the input sentences and predicting them based on the surrounding words. BERT was proposed for natural language understanding and generation in the paper BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding, and it has since been extended and adapted to various domains and tasks. BERT is available in PyTorch Text, and you can find the documentation and examples here.

These are just four more examples of models that can handle incomplete data in PyTorch. There are many other models and techniques that can be used for this purpose, depending on the type and amount of missing data, the domain and task, and the desired outcome. You can find more information and resources about PyTorch models and machine learning based on incomplete data in the following links:

  • PyTorch Models - GitHub
  • [Train deep learning PyTorch models (SDK v2) - Azure Machine Learning]
  • [How to Train and Deploy a Linear Regression Model Using PyTorch - Docker]
  • [PyTorch Tutorial: How to Develop Deep Learning Models with Python]

I hope this answer was helpful. If you have any other questions, please feel free to ask me. 😊

These are just two examples of models that can handle incomplete data in PyTorch. There are many other models and techniques that can be used for this purpose, depending on the type and amount of missing data, the domain and task, and the desired outcome. You can find more information and resources about PyTorch models and machine learning based on incomplete datawith the following key words:

  • [PyTorch Models - GitHub]
  • [Train deep learning PyTorch models (SDK v2) - Azure Machine Learning]
  • [How to Train and Deploy a Linear Regression Model Using PyTorch - Docker]
  • [PyTorch Tutorial: How to Develop Deep Learning Models with Python]

What is the difference between DenseNet and ResNet?

How can I handle missing data in PyTorch?

There are different ways to handle missing data in PyTorch, depending on the type and amount of missing data, the domain and task, and the desired outcome. Some of the common methods are:

  • Dropping the rows or columns that have missing values. This is a simple and fast way to deal with missing data, but it can also reduce the amount and quality of the data, and introduce bias or loss of information.
  • Imputing the missing values with some appropriate values, such as the mean, median, mode, or a constant. This is a way to preserve the data and avoid bias, but it can also introduce noise or distortion, and affect the variance and distribution of the data.
  • Using masking techniques to indicate which values are missing, and predicting them based on the context. This is a way to learn from the residual information in the data, and avoid noise or distortion, but it can also increase the complexity and computation of the model.
  • Using models that are inherently robust to incomplete data, such as ResNet or Transformers, which can learn from the residual features or dependencies in the data, and avoid the problem of vanishing or exploding gradients.

You can find more information and examples about how to handle missing data in PyTorch in the following links:

Sunday, December 3, 2023

💥💥💥 How to communicate Ansys Fluent with Siemens Simit (possible ways) ?

 To communicate Ansys Fluent with Siemens Simit, you may need to use the Functional Mock-up Interface (FMI) standard, which is a tool-independent standard for the exchange and co-simulation of dynamic models. FMI defines a common interface for model exchange and co-simulation, which allows different simulation tools to communicate and exchange information during the simulation process1.

One possible way to use FMI is to create a sub circuit using compatible elements in Twin Builder, and then compile a twin model out of the sub circuit. After that, you can select the twin model and export it as a twin for deployment2. You can also use the command /plot/file-set/plot-to-file [filename] to export the data used in the plots into a specified file3. However, Fluent only supports co-simulation FMU, which means that it cannot export FMU files by itself4. You may need to use another tool that supports FMI model exchange to create FMU files from Fluent data.


You can find more information and guidance on how to use FMI and FMU files in the following web search results:

Can I import output results file, for example CSV file from Ansys Fluent to Simit, without using Twin Buidler?

It seems that you want to import output results file, for example CSV file from Ansys Fluent to Simit, without using Twin Builder. According to the web search results, there are some possible ways to do that by using the Functional Mock-up Interface (FMI) standard, which is a tool-independent standard for the exchange and co-simulation of dynamic models. FMI defines a common interface for model exchange and co-simulation, which allows different simulation tools to communicate and exchange information during the simulation process1.

One possible way to use FMI is to export the data used in the plots into a specified file by using the command /plot/file-set/plot-to-file [filename]2. Then, you can use another tool that supports FMI model exchange to create FMU files from Fluent data. For example, you can use Simulink, which is a graphical environment for modeling, simulation and analysis of multi-domain systems. Simulink can import and export FMU files and perform co-simulation with other FMI-compatible tools3.

Another possible way to use FMI is to write the result of Fluent into a generic ASCII file which you can then read elsewhere4. Then, you can use a tool that can convert the ASCII file into an FMU file, such as FMPy, which is a Python library to simulate FMU files5.

You can find more information and guidance on how to use FMI and FMU files in the following web search results:

Can I use Fluent with other simulation tools that support FMI?

Yes, you can use Fluent with other simulation tools that support FMI. FMI is a tool-independent standard for the exchange and co-simulation of dynamic models. FMI defines a common interface for model exchange and co-simulation, which allows different simulation tools to communicate and exchange information during the simulation process1.

Some of the simulation tools that support FMI are:

  • Simulink: Simulink is a graphical environment for modeling, simulation and analysis of multi-domain systems. Simulink can import and export FMU files and perform co-simulation with other FMI-compatible tools.
  • PSIM: PSIM is a simulation software for power electronics, motor drives, and power systems. PSIM can generate FMU models and perform co-simulation with other FMI-supporting software.
  • Wolfram System Modeler: Wolfram System Modeler is a Modelica-based modeling and simulation tool that supports FMI for model exchange and co-simulation. System Modeler can import and export FMU files and also integrate with other Wolfram products.

You can find more information and guidance on how to use FMI and FMU files in the following web search results:

What is the difference between FMI and FMU?

The difference between FMI and FMU is that FMI is a standard for the exchange and co-simulation of dynamic models, while FMU is a file that contains a simulation model that adheres to the FMI standard1. FMI defines a common interface for model exchange and co-simulation, which allows different simulation tools to communicate and exchange information during the simulation process. FMU is a file that consists of an XML description file and implementation in a binary form2. FMU can be imported or exported by different simulation tools that support the FMI standard. FMI and FMU are part of the same FMU standard for the purpose of system integration, which simplifies the interaction between the simulation environment and the systems models in different domains3. FMU represents the simulation model, while FMI provides a standardized communication interface between the models.

Is there possibility to create FMU file in Ansys Fluent ?

According to the web search results, it seems that there are some modules in Ansys Workbench that can create FMU files. FMU files are files that contain a simulation model that adheres to the Functional Mock-up Interface (FMI) standard, which is a tool-independent standard for the exchange and co-simulation of dynamic models1.

Some of the modules that can create FMU files are:

You can find more information and guidance on how to use FMI and FMU files in the following web search results:

How do I create an FMU file from Ansys Mechanical data?

To create an FMU file from Ansys Mechanical data, you need to use the FMI Export feature in Ansys Mechanical. FMU files are files that contain a simulation model that follows the Functional Mock-up Interface (FMI) standard, which is a tool-independent standard for the exchange and co-simulation of dynamic models1.

The FMI Export feature allows you to export your Mechanical model as an FMU file for co-simulation with other FMI-compatible tools. You can access the FMI Export feature by right-clicking on the Solution branch in the Mechanical outline and selecting FMI Export2. You can then specify the name and location of the FMU file, the FMI version, the co-simulation type, and the input and output variables. You can also select the option to include the results file in the FMU file, which will allow you to initialize the FMU with the results from the Mechanical solution3.

After you export the FMU file, you can import it into another tool that supports FMI co-simulation, such as Ansys Twin Builder, Simulink, or Open Modelica. You can then perform co-simulation between the Mechanical model and the other model, and exchange data and parameters between them. You can find more information and guidance on how to use FMI and FMU files in the following web search results:

Can I create FMU file in Ansys CFX ?

Saturday, December 2, 2023

💥💥💥 What are The prons and cons comparing Ansys Fluent and CFX ?

 Ansys Fluent and CFX are both powerful computational fluid dynamics (CFD) software tools that can help you solve complex fluid flow problems. However, they have some differences in their features, capabilities, and applications. Here are some of the pros and cons of each tool based on the information I found on the web:

Ansys Fluent:

Pros:

- Fluent can handle true 2D meshes, which can reduce the computational cost and time for some problems¹.

- Fluent can handle polyhedral and cutcell meshes, which can improve the accuracy and robustness of the solution¹.

- Fluent has stronger mesh adaption capabilities than CFX, which can help refine the mesh in regions of interest and improve the solution quality¹⁴.

- Fluent has its own post-processing capabilities, which can help visualize and analyze the results within the same environment¹.

- Fluent is continuously updated and improved by the developers, and has more tutorials and resources available for learning¹.

- Fluent can simulate high Mach number flows (supersonic and hypersonic flows), which are important for aerospace applications¹.

- Fluent can use GPU acceleration to speed up the simulation, which can save time and resources¹.


Cons:

- Fluent uses a semi-implicit solver, which can be slower than CFX for some problems¹.

- Fluent uses a cell-centered approach, which can introduce errors in the pressure-velocity coupling¹.

- Fluent needs user-defined functions (UDFs) for customization, which can complicate things for beginners¹⁴.


Ansys CFX:

Pros:

- CFX uses a fully implicit solver, which can be faster than Fluent for some problems¹.

- CFX uses a vertex-centered approach, which can avoid errors in the pressure-velocity coupling¹.

- CFX uses a shape function borrowed from finite element method (FEM) to evaluate gradients, which can improve the accuracy and stability of the solution¹.

- CFX can use CFX Expression Language (CEL) for customization, which is easier and more flexible than UDFs¹⁴.

- CFX can handle turbomachinery problems, which are important for power generation and propulsion applications¹.


Cons:

- CFX cannot handle true 2D meshes, which can increase the computational cost and time for some problems¹.

- CFX cannot handle polyhedral and cutcell meshes, which can limit the meshing options and solution quality¹.

- CFX has weaker mesh adaption capabilities than Fluent, and only supports adaptive meshing for single domains with no GGI interfaces and limited physics¹⁴.

- CFX needs a dedicated post-processor, which can add an extra step and complexity to the workflow¹.

- CFX is not updated and improved as frequently as Fluent, and has fewer tutorials and resources available for learning¹.

- CFX cannot simulate high Mach number flows (supersonic and hypersonic flows), which are relevant for aerospace applications¹.

- CFX cannot use GPU acceleration to speed up the simulation, which can waste time and resources¹.

I hope this helps you compare Ansys Fluent and CFX. If you want to learn more about them, you can visit their official websites²³ or read some user reviews⁴..

Source:

(1) CFX vs. FLUENT -- CFD Online Discussion Forums. https://www.cfd-online.com/Forums/cfx/166388-cfx-vs-fluent.html.

(2) Compare Ansys CFX vs. Ansys Fluent | G2. https://www.g2.com/compare/ansys-cfx-vs-ansys-fluent.

(3) . https://bing.com/search?q=Ansys+Fluent+vs+CFX+pros+and+cons.

(4) What are the differences between CFX and Fluent? - Ansys Learning Forum. https://forum.ansys.com/forums/topic/what-are-the-differences-between-cfx-and-fluent/.

(5) https://www.cfd-online.com/Forums/cfx/110640-difference-between-ansys-cfx-fluent.html.

(6) https://www.gettyimages.com/detail/news-photo/in-this-photo-illustration-the-ansys-logo-seen-displayed-on-news-photo/1212478964.

What is the difference between a semi-implicit solver and a fully implicit solver?

A semi-implicit solver and a fully implicit solver are two types of numerical methods for solving differential equations that arise in computational fluid dynamics (CFD). The main difference between them is how they treat the terms that depend on the unknown quantities at the new time step¹.

A semi-implicit solver evaluates some of the terms in the equation using the known quantities at the previous time step, while a fully implicit solver evaluates all of the terms using the unknown quantities at the new time step¹. This means that a fully implicit solver requires solving a system of equations involving both the current and the new state of the system, while a semi-implicit solver can calculate the new state directly from the current state¹.

The advantage of a fully implicit solver is that it can be more stable and accurate than a semi-implicit solver, especially for stiff problems where the time step size is limited by stability issues¹². The disadvantage of a fully implicit solver is that it can be more computationally expensive and complex to implement than a semi-implicit solver, especially for non-linear problems where the system of equations needs to be solved iteratively¹².

The choice of a semi-implicit or a fully implicit solver depends on the problem to be solved, the desired accuracy and efficiency, and the availability of certain features. For example, some problems may require a fully implicit solver to handle dynamic effects, contact, or certain physics models, while others may benefit from a semi-implicit solver to handle high-speed flows, mesh adaptation, or GPU acceleration²³.

Source:

(1) Explicit and implicit methods - Wikipedia. https://en.wikipedia.org/wiki/Explicit_and_implicit_methods.

(2) Implicit Vs Explicit Finite Element Analysis: When to Use Which? - TECHNIA. https://simulation-blog.technia.com/simulation/implicit-vs-explicit-finite-element-analysis.

(3) Implicit vs. Explicit Numerical Methods - FLOW-3D. https://www.flow3d.com/resources/cfd-101/numerical-issues/implicit-versus-explicit-numerical-methods/.

Friday, December 1, 2023

💥💥💥 What are the methods of modeling the closed gas cycle in Ansys Fluent?

 There are several methods of modeling the closed gas cycle in Ansys Fluent, depending on the type of problem, the assumptions, and the desired results. Some of the possible methods are:


For more information and examples of modeling the closed gas cycle in Ansys Fluent, you can refer to the following sources:
How do I model heat transfer in a closed gas cycle?

To model heat transfer in a closed gas cycle, you need to solve the energy equation for the gas flow, in addition to the continuity and momentum equations. The energy equation is a statement of the first law of thermodynamics, which relates the changes in internal energy, kinetic energy, and potential energy of the gas to the heat and work transfer across the system boundary. 

Ansys Fluent can solve the energy equation for the gas flow using various methods and models, depending on the type of problem, the assumptions, and the desired results. Some of the possible methods and models are:

For more information and examples of modeling heat transfer in a closed gas cycle in Ansys Fluent, you can refer to the following sources:

  • Energy Equation - Ansys Fluent Theory Guide, which is a document that explains the formulation, discretization, and solution methods of the energy equation in Ansys Fluent.
  • Materials - Ansys Fluent User’s Guide, which is a document that describes how to define the material properties and the specific heat models in Ansys Fluent.
  • Compressible Flows - Ansys Fluent User’s Guide, which is a document that shows how to set up and solve compressible flow problems in Ansys Fluent.
  • [Heat Transfer - Ansys Fluent User’s Guide], which is a document that illustrates how to enable and use the heat transfer models and the thermal boundary conditions in Ansys Fluent.
How to define mass source term in closed loops in Ansys Fluent?

To define a mass source term in a closed loop in Ansys Fluent, you need to use a user-defined function (UDF) that specifies the amount of mass added or removed from the system. You can write the UDF in C language and compile it in Ansys Fluent using the DEFINE_SOURCE macro. The UDF should return the value of the mass source term in units of kg/m^3 s for each cell in the domain. You can also use Fluent expressions and cell registers to define the mass source term based on spatial coordinates or other variables. You can apply the UDF to a cell zone, a face zone, or a point in the Cell Zone Conditions menu. You can also use the Phase Interaction menu to define the mass transfer terms between different phases in a multiphase flow.

For more information and examples of defining mass source terms in closed loops in Ansys Fluent, you can refer to the following sources:

Are there other methods to define mass source terms instead of defining UDF in Ansys Fluent?

Yes, there are other methods to define mass source terms instead of defining UDF in Ansys Fluent. Some of the possible methods are:

For more information and examples of defining mass source terms using these methods in Ansys Fluent, you can refer to the sources that I found in my web search.

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