RWIND 2 | Wind Simulation (Wind Tunnel)

Features of RWIND Basic

• 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, etc.)
• 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, and Russian)
• 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)

Features of RWIND Pro

• 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

Input

RFEM and RSTAB have a special interface for exporting models (i.e. structures defined by members and surfaces) to RWIND Basic. In this interface, the wind directions to be analyzed are defined by means of related angular positions about the vertical model axis, and the height-dependent wind and turbulence intensity profile is defined on the basis of a wind standard. Based on this information, you can use stored calculation parameters for a stationary calculation for each angular position.

You can also run the RWIND Basic program manually without the interface in RFEM and RSTAB. In this case, the structures and terrain environment in RWIND Basic are directly modeled by importing VTP, STL, OBJ, and IFC files. The height-dependent wind load and other fluid-mechanical data can be defined directly in RWIND Basic.

Calculation

RWIND Basic uses a numerical CFD model (Computational Fluid Dynamics) to simulate wind flows around objects using a digital wind tunnel. The simulation process determines specific wind loads on the model surfaces from the flow result around the model.

A 3D volume mesh is used for the simulation. RWIND Basic performs an automatic meshing on the basis of freely definable control parameters. For the calculation of wind flows, RWIND Basic provides a stationary solver, while 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.

Output

The solution of the numerical flow problem gives results on and around the model:

• Pressure on structure surface
• Coefficient Cp distribution on the structure surfaces
• Pressure field about structure geometry
• Velocity field about structure geometry
• Turbulence k-ω field about structure geometry
• Turbulence k-ε field about structure geometry
• Velocity vectors about structure geometry
• Streamlines about 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

These results are displayed in the RWIND environment and evaluated graphically for freely definable zones. Since voluminously displayed flow results about the structure geometry are confusing, RWIND Basic provides freely movable section planes for the separate display of the "solid results" in a plane. In addition to a static display, there is also an animated display in the form of moving line segments or particles for the 3D branched streamline result. This option helps to represent the wind flow as a dynamic effect.

All results can be exported as an image or, especially for the animated results, as a video.