How can I keep the number of mesh elements in the model down for the numerical flow analysis despite a very fine model contour?

Answer

The activated model simplification allows for RWIND Simulation to generate a "shrink-wrapping" mesh similar to a shrink wrap around the model geometry before the actual finite solid meshing. The program uses the target mesh size of this wrapping mesh from the respectively assigned detail level of the model. This minimum mesh size specifies the finite volume element size in surroundings to the wrapping mesh and additionally specifies the finite volume mesh size distribution between the wrapping mesh on the model and the wind tunnel boundary surfaces in cooperation with the globally defined mesh density. The fine meshing in the model surroundings is necessary for a good determination of the turbulence effect and a real boundary layer distribution.

However, since the resulting pressures on the model geometry are adjusted by transformation at the transition points between the finite volume mesh and the wrapping mesh, the wrapping mesh does not necessarily have to have the same mesh geometry as the enclosing finite volume mesh. This fact allows for an optimization of the wrapping mesh geometry with regard to the number of elements with a variable size distribution to determine the correct geometry.

Figure 01 - Mesh Arrangement

Such an optimization of the simplified "shrink-wrapping" mesh geometry can be activated in RWIND Simulation by using the optimization option in the model properties. To control the number of elements on the wrapping mesh geometry, you can specify an expected number of elements with the minimum and the maximum limit value in the option properties.

Figure 02 - Optimization of Wrapping Mesh Geometry

Figure 03 - Finite Volume Mesh Geometry in Model Surroundings

Figure 04 - Optimized Wrapping Mesh Geometry with Reduced Number of Elements

Keywords

Optimization Meshing Relief Finite elements Finite volume

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RFEM Main Program
RFEM 5.xx

Main Program

Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements

Price of First License
3,540.00 USD
Compatible Programs RWIND Simulation
RWIND Simulation 1.xx

Stand-Alone Program

Stand-alone program for numerical simulations of wind flow around buildings or any other objects. The generated wind loads acting on these objects can be imported into RFEM / RSTAB programs for static and dynamic analysis.

Price of First License
2,690.00 USD