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.
The stand-alone program RWIND 3 takes care of fresh air. It is used for the numerical simulation of wind flow and is available in a Basic as well as a Pro version. What additional features does RWIND Pro offer you? It allows for the calculation of transient incompressible turbulent wind flows (in addition to the stationary ones in RWIND Basic). But that's not all. Intrested in learning more? Find out more here:
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 body geometry are usually confusing – you are likely already familiar with this problem. 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.
To model structures in RWIND Basic, you find a special application in RFEM and RSTAB. Here, you can 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 flow, RWIND Basic provides a steady solver and RWIND Pro a transient solver for incompressible turbulent flow. Surface pressures resulting from the flow results are extrapolated onto the model for each time step.
If you are looking for models to practice on or as inspiration for your projects, you've come to the right place. We offer a vast number of structural analysis models to download, such as RFEM, RSTAB, or RWIND files.
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.
Rely on the Dlubal programs even in windy matters. RFEM and RSTAB provide a special interface for exporting models (that is, structures defined by members and surfaces) to RWIND 2. There, the wind directions to be analyzed for your project are defined by means of related angular positions about the vertical model axis. Furthermore, the elevation-dependent wind profile and turbulence intensity profile are defined on the basis of a wind standard. These specifications result in specific load cases, depending on the angle. For this, the fluid parameters, turbulence model properties, and iteration parameters that are all stored globally are helpful. You can extend these load cases by partial editing in the RWIND 2 environment using terrain or environment models from STL vector graphics.
As an alternative, you can also run RWIND 2 manually and without the interface application in RFEM or RSTAB. In this case, the structures and terrain environment in the program are directly modeled by imported STL and VTP files. You can define the height-dependent wind load and other fluid-mechanical data directly in RWIND 2.
Due to its versatile applicability, RWIND 2 is always at your side to support you in your individual projects.
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:
The meshing algorithm of RWIND Simulation uses the boundary layer option to mesh the area near the model surface with a voluminous layer mesh. The number of layers is controlled by a user-defined parameter.
This fine mesh in the area of the model surface helps to represent the wind velocity close to the surface.
Work on your models with efficient and precise calculations in the digital wind tunnel. RWIND 2 verwendet zur Simulation von Windströmungen um Objekte ein numerisches CFD-Modell (Computational Fluid Dynamics). Specific wind loads are generated from the simulation process for RFEM or RSTAB.
Diese Simulation führt RWIND 2 mithilfe eines 3D-Volumennetzes durch. Das Programm sorgt für eine automatische Vernetzung, wobei Sie die gesamte Netzdichte und die lokale Netzverdichtung am Modell ganz einfach mit wenigen Parametern einstellen können. A numerical solver for incompressible turbulent flows is used to calculate the wind flows and the surface pressures on the model. Die Ergebnisse werden dann an Ihrem Modell extrapoliert. RWIND 2 ist so konzipiert, dass es mit verschiedenen numerischen Solvern funktioniert.
Aktuell empfehlen wir Ihnen, das
OpenFOAM
®-Softwarepaket zu verwenden, welches in unseren Tests sehr gute Ergebnisse liefert und zudem ein weitverbreitetes Tool für CFD-Simulationen ist. Alternative numerical solvers are under development.
In RWIND Simulation, it is possible to divide the model in different zones. This allows for different surface roughness to be assigned to the zones. In addition, local results can be better evaluated.
Utilize the RWIND Simulation program to consider a surface roughness of the model surface by applying a modified wall boundary condition. The numerical model is based on the assumption that grains with a certain diameter are arranged homogeneously on the model surface, similar to sandpaper. The grain diameter is described with the parameter Ks and the distribution with the parameter Cs. By considering the wall roughness, the numerical flow simulation can capture reality more closely.
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)
Always keep an eye on your results. In addition to the resulting load cases in RFEM or RSTAB (see below), the results from the aerodynamics analysis in RWIND 2 represent the flow problem as a whole:
Pressure on structure surface
Pressure field about structure geometry
Velocity field about structure geometry
Velocity vectors about structure geometry
Flow lines 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 2 environment and evaluated graphically. The flow results around the structure geometry in the overall display are rather confusing, but the program has a solution for this. In order to present clearly arranged results, freely movable section planes are displayed for the separate display of the 'solid results' in a plane. Accordingly, for the 3D branched streamline result, the program presents you an animated display in the form of moving lines or particles in addition to the static one. This option helps 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.
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.