We provide hints and tips to help you get started with the RFEM program.
FAQ 004513 | How can I keep the number of mesh elements in the model down for the numerical flow analysis despite a very fine model contour?
First Steps with RFEM
QuestionHow can I keep the number of mesh elements in the model down for the numerical flow analysis despite a very fine model contour?
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.
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.
Do you have any questions about our products or need advice on selecting the products needed for your projects?
Contact us via our free e-mail, chat, or forum support or find various suggested solutions and useful tips on our FAQ page.
Models to Download
Surface Model of Wind Pressure Distribution on China Central Television Headquarters Building
Knowledge Base Articles
Computer technology has a firm grip on digital structural analysis and design. With each new development, the involved planners are able to push the limits of what is feasible upwards.
Product Features Articles
The results of the form‑finding process are a new shape and corresponding inner forces. Usual results such as deformations, forces, stresses, and others can be displayed in the RF‑FORM‑FINDING case.
This prestressed shape is available as the initial state for all other load cases and combinations in the structural analysis.
For more ease when defining load cases, the NURBS transformation can be used (Calculation Parameters / Form‑Finding). This feature moves the original surfaces and cables into the position after form‑finding.
By using the grid points of surfaces or the definition nodes of NURBS surfaces, free loads can be situated on selected parts of the structure.
Frequently Asked Questions (FAQ)
- I have defined a wind profile for RWIND Simulation up to a height of 100 m. Is the wind profile dependent on the size of the wind tunnel?
- How can I import an IFC model into the RWIND Simulation environment?
- Why is the surface pressure distribution in RFEM different from the corresponding surface pressure distribution in RWIND Simulation?
- I would like to use the export of visual objects to RWIND Simulation. How do I scale my visual object for the import?
- How can I adjust the wind tunnel to the model in RWIND Simulation?
- Where are the RWIND Simulation projects created by RFEM/RSTAB saved?
- In RWIND Simulation, I imported neighboring buildings and terrain to consider them. When performing a new calculation in RWIND Simulation, started from RFEM, this data is no longer available. What can I do?
- How can I keep the number of mesh elements in the model down for the numerical flow analysis despite a very fine model contour?
- Where can I define a wind velocity diagram according to a specific wind standard for the numerical wind tunnel analysis in RWIND Simulation?
- How can I access the RWIND Simulation program from RFEM, assuming that it is possible to transfer a 3D model created in RSTAB?