💥💥💥 How to create multi zones for meshing in Ansys Fluent ?

Ansys Fluent is a powerful computational fluid dynamics (CFD) software that can simulate various fluid phenomena such as turbulence, heat transfer, multiphase flow, and more. One of the features of Ansys Fluent is the ability to create different types of zones for different regions of interest in a geometry. Zones are collections of cells that share the same properties and boundary conditions. You can use zones to simplify the meshing process and reduce the computational cost.

There are different ways to create multi zones for meshing in Ansys Fluent, depending on your geometry and your objectives. Here are some possible methods:

- **Using the Zone Type Manager**: This method allows you to create multiple types of zones from a single geometry, such as solid, fluid, or mixed. You can then assign different properties and boundary conditions to each zone type. To use this method, you need to open the Zone Type Manager from the Meshing menu or by clicking on the Zone Type icon in the toolbar. Then you can select the zone type in the Multiple Types list and choose two or more zones in the Zones of Type list. You can also edit or delete existing zone types from this window³.

- **Using Cell Zone Separation**: This method allows you to separate a single cell zone into multiple zones by using different criteria, such as region name, region number, region type, or region size. You can then assign different properties and boundary conditions to each zone separately. To use this method, you need to open the Cell Zone Separation dialog box from the Meshing menu or by clicking on the Cell Zone Separation icon in the toolbar. Then you can select a cell zone and choose one or more criteria from the Criteria list. You can also edit or delete existing cell zones from this dialog box³.

- **Using Multiblock Meshing**: This method allows you to create multiple cell zones by generating a multiblock mesh that consists of several submeshes connected by faces or edges. You can then allocate different fluids to each submesh and assign different properties and boundary conditions accordingly. To use this method, you need to open the Multiblock Mesh dialog box from the Meshing menu or by clicking on the Multiblock Mesh icon in the toolbar. Then you can select a multiblock mesh option from the Options list and specify one or more submeshes from the Submeshes list³.

- **Using Watertight Geometry Workflow**: This method allows you to create multiple fluid regions with interfaces between them using a watertight geometry workflow that preserves continuity across boundaries. You can then apply share topology options to merge adjacent regions into one cell zone with shared properties and boundary conditions². To use this method, you need to open the Watertight Geometry Workflow dialog box from the Meshing menu or by clicking on the Watertight Geometry Workflow icon in

the toolbar. Then you can select a watertight geometry workflow option from

the Options list and specify one or more regions with interfaces from

the Regions list².

Source: 

(1) ANSYS FLUENT 12.0 User's Guide - 6.8.1 Merging Zones - ENEA. https://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node203.htm.

(2) Multiple-Cell (fluid) Zone Meshing in Ansys Fluent. https://forum.ansys.com/forums/topic/multiple-cell-fluid-zone-meshing-in-ansys-fluent/.

(3) how to create multiple fluid zones and an interface. https://www.cfd-online.com/Forums/fluent/151383-how-create-multiple-fluid-zones-interface.html.

(4) Contact connection between multiple surfaces - Ansys Learning Forum. https://forum.ansys.com/forums/topic/contact-connection-between-multiple-surfaces/.

What are the advantages of using multi zones?

Using multi zones in Ansys Fluent can have several advantages, depending on your geometry and your objectives. Some of the possible benefits are:

- **Improved mesh quality**: Multi zones can reduce the cell count significantly by creating more efficient and structured meshes that cover the regions of interest. This can improve the accuracy and stability of the simulation⁴.

- **User control**: Multi zones allow you to create different types of zones for different regions, such as solid, fluid, or mixed. You can then assign different properties and boundary conditions to each zone type, such as density, viscosity, pressure, temperature, etc. This gives you more flexibility and control over the simulation³.

- **Boundary condition flexibility**: Multi zones enable you to impose boundary conditions on different regions using different methods, such as wall, inlet/outlet, surface, or volume. You can also use multiple fluid-solid interfaces or multiple fluid-fluid interfaces to model complex flow scenarios².

- **Rendering choices**: Multi zones can provide more choices for rendering the mesh and the flow-field solution by allowing you to select different surfaces for display. You can also use multiblock meshing or watertight geometry workflow to create multiple cell zones with interfaces between them¹.

Source: 

(1) Introduction toIntroduction to ANSYS FLUENT - iMechanica. https://imechanica.org/files/fluent_13.0_lecture03-solver-basics.pdf.

(2) ANSYS FLUENT 12.0 User's Guide - 6.8.1 Merging Zones - ENEA. https://www.afs.enea.it/project/neptunius/docs/fluent/html/ug/node203.htm.

(3) Multiple Zones in Wall Boundary Condition - Ansys Learning Forum. https://forum.ansys.com/forums/topic/multiple-zones-in-wall-boundary-condition/.

(4) Ansys 2022 R2: What's New in Ansys Fluent Multizone Meshing. https://www.ansys.com/webinars/whats-new-in-ansys-fluent-multizone-meshing.

Can you explain more about watertight geometry workflow?

Sure, I'll be happy to explain more about the watertight geometry workflow in Ansys Fluent. The watertight geometry workflow is a method to create a mesh that is CFD-ready in minutes. It is an intuitive guided workflow that streamlines the whole end-to-end process of importing a watertight or clean CAD geometry, creating a surface mesh, describing the geometry and extracting fluid regions, and generating a complete volume mesh³.

The watertight geometry workflow has several advantages over other methods of meshing, such as:

- It is easy to use and does not require any advanced skills or experience.

- It can handle complex geometries with multiple solids, interfaces, and boundaries.

- It can create high-quality meshes with minimal user intervention and maximum automation.

- It can save time and resources by reducing the number of manual steps and iterations.

The watertight geometry workflow consists of the following steps:

- **Import CAD geometry**: You can import your CAD model into Ansys Fluent using various formats, such as STEP, IGES, STL, etc. You can also use native Fluent files (.pmdb) that are created by Fluent when you import your model for the first time.

- **Create local sizing**: You can optionally add local sizing to your model to control the size of each cell zone. This can help you optimize the mesh quality and reduce the computational cost.

- **Create surface mesh**: You can create a surface mesh for your model using different algorithms, such as adaptive mesh refinement (AMR), multiblock meshing (MBM), or multiblock volume meshing (MBVM). These algorithms can improve the accuracy and stability of the simulation by creating more efficient and structured meshes.

- **Describe geometry**: You can describe your geometry using different tools, such as symmetry planes, symmetry groups, or symmetry operators. These tools can help you identify and define regions of interest in your model that have special properties or boundary conditions.

- **Extract fluid regions**: You can extract fluid regions from your model using different methods, such as capping tools, fluid-solid interfaces (FSI), or fluid-fluid interfaces (FFI). These methods can help you model complex flow scenarios where there are multiple fluids or solid bodies involved.

- **Generate volume mesh**: You can generate a volume mesh for your model using different options, such as automatic volume generation (AVG), manual volume generation (MVG), or hybrid volume generation (HVG). These options can help you create a complete CFD-ready mesh that covers all regions of interest in your model.

Source: 

(1) Fluent: Watertight Geometry Meshing Workflow - Ansys Knowledge. https://ansyskm.ansys.com/forums/topic/fluent-watertight-geometry-meshing-workflow/.

(2) Ansys Fluent Watertight Geometry Workflow | Ansys Webinar. https://www.ansys.com/resource-center/webinar/ansys-fluent-watertight-geometry-workflow.

(3) How to Mesh Watertight CFD Geometry in Ansys Fluent. https://www.ansys.com/blog/watertight-cfd-geometry-ansys-fluent.

(4) Tutorial on Watertight Geometry Workflow | Ansys Courses. https://courses.ansys.com/index.php/courses/workshops/.

(5) How to Mesh with Watertight Geometry Workflow - Lesson 1. https://courses.ansys.com/index.php/courses/user-interface/lessons/how-to-mesh-with-watertight-geometry-workflow-lesson-1/.