How to... define cylindrical anisotropic conductivity in Ansys Fluent (cyl-orthotropic)

Many of the problems that are modeled in CFD today concern multi-layer objects. It often happens that these  models have large sizes and thin layers. Due to this specificity, we have certain conduction properties in various directions of solid body. Drawing such models in the 1: 1 scale causes many problems, primarily related to the generation of a very large number of finite elements. Sometimes the computer hardware parameters do not allow us to perform such an analysis.

Cyl-orthotropic in Ansys Fluent 

How to... define quasi porous material in Transient Thermal (material combination)

 A very interesting option in newer versions of Ansys Workbench is defining materials consisting of several components.  It is especially useful because the program automatically updates the physical and thermal properties of the new defined mixture.  It is possible to create, for example, porous materials consisting of a solid and a fluid.

How to... simplify case when Your Fluent Structural FSI doesn't work ?

It often happens that we want to do a coupled analysis consisting of two CFD and Structural modules. The purpose of FSI analyzes is to set the thermal conditions that came out from CFD simulation to the Structural analysis as boundary conditions. In the module for mechanical calculations itself, we cannot set a heterogeneous temperature profile, therefore it is necessary to perform two analyzes in these cases as FSI. A very common problem in this type of analysis is a bad transfer of thermal conditions to the Structural module. The distribution of values is not the same as what we came out with CFD. Therefore, in these cases, you can simplify the analysis by adding one more Transient Thermal module from which the transfer of temperature distributions is burdened with a much smaller error.

III stages for simplify FSI case

How to... fix error Floating Point Exception -Overflow in Ansys CFX ?

 Many times, during the implementation of numerical modeling, after completing the boundary and initial conditions and starting the solver we have to do with a sudden stop of the analysis and the appearance of an overflow message.  This is the most common type of error that occurs when performing CFD analysis.  In today's post, I would like to present two paths to minimize the appearance of this error.

Most often  error in CFX 

How to... choose radiation model in Ansys Fluent

 Many times in numerical modeling we have a dilemma whether we have to take into account the radiation model, and if so, what exactly to choose.  

Which model of radiation to pick in Fluent

How to... analyze and measure model in postprocessing CFX / Fluent Ansys

After many analyzes, we come to the conclusion that each elaboration of the results looks similar (sometimes identical).  Then it's time to diversify our report with new indicators and charts.  Ansys postprocessing offers many possibilities.  First of all, we can display our output with different configurations of contours, velocity vectors or isosurfaces.

Path to generate measuring  lines

How to... perform a temperature dependent analysis without an Energy Model Ansys Fluent

 There is often a need to model the gas flow in specific systems with a temperature other than 25 C. Then we include the Energy model in the standard modeling procedure. The number of subsequent models taken into account in our analysis significantly extends the computation time. This is mainly due to the fact that the program has to solve additional equations (in our case, equations related to heat transfer). If our goal is not the temperature distribution in the analyzed domains, then we can simplify the analysis by omitting the Energy model.

How to define gas properties in Fluent 

How to... define monitors (report definitions) in Ansys Fluent

 There is often a situation when, after completing the analysis and obtaining a satisfactory level of partial equations, we may be unpleasantly surprised when we for example plot the  temperature in the RESULTS module. 

Example of monitor in Fluent

How to... move global coordinate systems (reference frames) to axis of rotation Ansys Fluent

An important element of each CFD and structural simulation is the precise definition of the global coordinate system. An improperly located coordinate system can lead to many difficulties - primarily in analyzes where the movement of individual elements is defined.

Example of bad geometry position vs coordiante system 

How to... increase /decrease time step size in Ansys Fluent

 Today I would like to show you how easy it is to control the  analysis in Fluent. All the necessary items can be found in the solver under Run Calculation menu. This is where the coefficients can be modified on an ongoing basis so that our residual equations are at the required level. 

Example of residual plot in Fluent 

How to... define precision of simulation and the criterion of convergence Ansys Fluent

 An important step in modeling is to define the precision of calculations and the criterion of convergence. 

How to define precision of solver in Fluent

The figure above shows the definition of static analysis based on the Courant number

How to... define motion in Ansys Fluent - sliding mesh

 In many problems that we want to model, we can meet with the movement of one or more elements. This is one of the three methods available from Ansys Fluent. The others are MRF and SRF (multi refernece frame, single reference frame). Sliding mesh is a traffic definition method for transient analyzes. The other methods can be used both in static and transient. They will be described in more detail in the following entries. In this post we will try to show you how to use the sliding mesh method. 

How to add motion on parts in Fluent 

How to... fix "gui-domain-label: no domain selected" in Ansys Fluent and MEMERR in CFX

In today's post, we will deal with another error that may occur during the analysis. The error that is described below concerns Fluent and the wrong definition of user monitors that are displayed during simulation. These can be monitors concerning the average velocity in the domain volume, the values of the maximum temperatures of the solid domains, the average values of the heat transfer coefficient from the defined planes of the model, etc. Generally speaking, today's entry is about how to correctly define monitors and how to transfer them between subsequent analyzes.

Example of "gui-domain-label" error in Fluent 

How to... correctly mesh CFD model in Ansys CFX and Fluent

Meshing is one of the decisive steps in both CFD and FEA analysis. The correct execution of the mesh and optimization in terms of the number of finite elements makes the work of every Ansys user much easier. 

Example of CFD mesh in Ansys Workbench

How to... make multi extrude in Design Modeler Ansys Workbench

 We often spend a lot of time on complex models ( geometry ) to simplify or modify them. There are several ways to make your work easier on 3D modelling. In design modeler there is a function that can be described as multi extrude (add / slice material). 

Many parts operations (extrude) in Ansys 

How to... slice geometry / model into smaller parts Ansys Workbench Design Modeler

Breaking down the model into smaller pieces can also be useful for creating subdomains. They can be useful for modeling quasi fans or separating zones for measuring the values we are looking for. Separating zones in the model can also be used to simplify the model - getting rid of elements / volumes that are irrelevant to us in the simulation. Separation can also be used to redefine the association of certain regions in our model. 

How to pick internal face in Design Modeler

How to... delete face - simplification geometry Design Modeler / Ansys Workbench

 In the Design Modeler module, we can find many functions that are designed to manipulate our model. We can move it freely, scale its dimensions, apply Boolean operations, round and chamfer edges, etc. Everything to make our model simpler and thus have fewer finite elements, which will shorten the calculations. In the case of Structural Analysis, we will also reduce the risk of the so-called single-node distortions of the obtained values (unrealistic, non-physical values of e.g. stresses).

How to delete face in Design Modeler

How to... choose additional options in turbulence models Ansys CFX

 Often, when choosing turbulence models in Ansys CFX, we do not focus on additional functions that we can use for our problem. Proper definition of the turbulent model in the analysis can have a decisive impact on the gas flow in the domains and on the overall fluid mechanics.

Additional options of turbulence in Ansys CFX