In RFEM and RSTAB, you can visualize the flow field quantities of pressure, velocity, turbulence kinetic energy, and turbulence dissipation rate for the wind simulation.
The clipping planes are aligned with the respective wind direction.
If you have experimentally determined surface pressures available for a model, you can apply them to a structural model in RFEM 6, process them in RWIND 2, and use them as wind loads in the structural analysis of RFEM 6.
You can find out how to apply the experimentally determined values in this Knowledge Base article: Static Analysis with Wind Loads from Experimentally Measured Pressures Using RWIND 2 and RFEM 6
You can display the RWIND results directly in the main program. In the Navigator - Results, select the Wind Simulation Analysis result type from the list above.
Currently, the following results are available, which refer to the RWIND computational mesh:
- Surface pressure
- Surface cp coefficient
- Wall distance y+ (steady flow)
Use RWIND 2 Pro to easily apply a permeability to a surface. All you need is the definition of
- the Darcy coefficient D,
- the inertial coefficient I, and
- the length of the porous medium in the direction of flow L,
to define a pressure boundary condition between the front and back of a porous zone. Due to this setting, you obtain the flow through this zone with a two-part result display on both sides of the zone area.
But that's not all. Furthermore, the generation of a simplified model recognizes permeable zones and takes into account the corresponding openings in the model coating. Can you waive an elaborate geometric modeling of the porous element? Understandable – we have good news for you then! With a pure definition of the permeability parameters, you can avoid complex geometric modeling of the porous element. Use this feature to simulate permeable scaffolding, dust curtains, mesh structures, and so on.
More InformationDo you already know the editor for mesh refinement control? It is a great help for your work! Why? It's easy – it gives you the following options:
- Graphic visualization of the areas with mesh refinements
- Mesh refinement of zones
- Deactivating the standard 3D solid mesh refinement with transversion into the corresponding manual 3D mesh refinements.
These options help you to formulate a suitable rule for meshing the entire model, even for the models with unusual dimensions. Use the editor to efficiently define small model details on large buildings or detailed meshing areas in the coating area of the model. You will be amazed!
- Calculation of stationary incompressible turbulent wind flow using the SimpleFOAM solver from the OpenFOAM® software package
- Numerical scheme according to the first and second order
- Turbulence models RAS k-ω and RAS k-ε
- Consideration of surface roughness depending on model zones
- Model design via VTP, STL, OBJ, and IFC files
- Operation via bidirectional interface of RFEM or RSTAB for importing model geometries with standard-based wind loads and exporting wind load cases with probe-based printout report tables
- Intuitive model changes via drag & drop and graphical adjustment assistance
- Generation of a shrink-wrap mesh envelope around the model geometry
- Consideration of environmental objects (buildings, terrain, and so on)
- Height-dependent description of the wind load (wind speed and turbulence intensity)
- Automatic meshing depending on a selected depth of detail
- Consideration of layer meshes near the model surfaces
- Parallelized calculation with optimal utilization of all processor cores of a computer
- Graphical output of the surface results on the model surfaces (surface pressure, Cp coefficients)
- Graphical output of the flow field and vector results (pressure field, velocity field, turbulence – k-ω field, and turbulence – k-ε field, velocity vectors) on Clipper/Slicer planes
- Display of 3D wind flow via animated streamline graphics
- Definition of point and line probes
- Multilingual user interface (German, English, Czech, Spanish, French, Italian, Polish, Portuguese, Russian, and Chinese)
- Calculations of several models in one batch process
- Generator for creating rotated models to simulate different wind directions
- Optional interruption and continuation of the calculation
- Individual color panel per result graphic
- Display of diagrams with separate output of results on both sides of a surface
- Output of the dimensionless wall distance y+ in the mesh inspector details for the simplified model mesh
- Determination of the shear stress on the model surface from the flow around the model
- Calculation with an alternative convergence criterion (you can select between the residual types pressure or flow resistance in the simulation parameters)
- Calculation of transient incompressible turbulent wind flow with the BlueDyMSolver solver
- LES SpalartAllmarasDDES turbulence model
- Consideration of stationary solution as initial state for transient calculation
- Automatic determination of analysis period and time steps
- Use of intermediate results during the calculation
- Organized display of time-varying results via time step units
- Diagram of drag force and point probe results over analysis time
- Display of line probe results for any time steps in a diagram
- Freely Adjustable Wind Permeability for Surfaces
To model structures in RWIND Basic, you find a special application in RFEM and RSTAB. Here, you define the wind directions to be analyzed by means of related angular positions about the vertical model axis. At the same time, you define the elevation-dependent wind profile on the basis of a wind standard. In addition to these specifications, you can use the stored calculation parameters to determine your own load cases for a stationary calculation per each angular position.
As an alternative, you can also use the RWIND Basic program manually, without the interface application in RFEM or RSTAB. In this case, RWIND Basic models the structures and terrain environment directly from the imported VTP, STL, OBJ, and IFC files. You can define the height-dependent wind load and other fluid-mechanical data directly in RWIND Basic.
RWIND Basic uses a numerical CFD model (Computational Fluid Dynamics) to simulate wind flows around your objects using a digital wind tunnel. The simulation process determines specific wind loads acting on your model surfaces from the flow result around the model.
A 3D volume mesh is responsible for the simulation itself. For this, RWIND Basic performs an automatic meshing on the basis of freely definable control parameters. For the calculation of wind flows, RWIND Basic provides you with a stationary solve and RWIND Pro provides a transient solver for incompressible turbulent flows. Surface pressures resulting from the flow results are extrapolated onto the model for each time step.
By solving the numerical flow problem, you can obtain the following results on and around the model:
- Pressure on structure surface
- Coefficient Cp distribution on the structure surfaces
- Pressure field about the structure geometry
- Velocity field about the structure geometry
- Turbulence k-ω field about the structure geometry
- Turbulence k-ε field about the structure geometry
- Velocity vectors about the structure geometry
- Streamlines about the structure geometry
- Forces on member-shaped structures that were originally generated from member elements
- Convergence diagram
- Direction and size of the flow resistance of the defined structures
Despite this amount of information, RWIND 2 remains clearly arranged, as is typical for the Dlubal programs. You can specify freely definable zones for a graphic evaluation. Voluminously displayed flow results about the structure geometry are often confusing – you know the problem for sure. That's why RWIND Basic provides freely movable section planes for the separate display of the "solid results" in a plane. For the 3D branched streamline result, you have an option to select between a static and an animated display in the form of moving line segments or particles. This option helps you to represent the wind flow as a dynamic effect.
You can export all results as a picture or, especially for the animated results, as a video.
When starting the analysis in the RFEM or RSTAB application, you trigger a batch process. It places all member, surface, and solid definitions of the model rotated with all relevant coefficients in the numerical wind tunnel of RWIND Basic. Furthermore, it starts the CFD analysis, and returns the resulting surface pressures for a selected time step as FE mesh nodal loads or member loads into the respective load cases of RFEM or RSTAB.
These load cases which contain RWIND Basic loads can then be calculated. Moreover, you can combine them with other loads in load and result combinations.