To get the best results from our numerical simulation, it is a good idea to check a few important things before running the calculation, these are discussed in the following subsections.
Detection 重叠 Triangles
原始模型可能包含“双三角形”，即位于同一平面内的重叠三角形，请参见下面的 图片。
The overlapping triangles can lead to wrong results, because the resulting pressure can be extrapolated to all these triangles and the total drag force acting on the model can be increased by that. 导入模型后，会自动激活重叠三角形的检查（参见章节导入模型），或者也可以从菜单中手动运行，参见下面的图像。
When you click on model check, a new window will open where you will find the conclusion and information about the number of overlapping triangles and their area.
重叠三角形的模型数据可以导出到文件中，然后在 ParaView 中显示和检查。
风洞
The outline of the wind tunnel is displayed as a box around the model in its center. You can check the wind direction, which is symbolized by a big red arrow. 在“项目导航器”中，有多个选项可用于显示与风洞相关的某些项目（参见图片项目导航器）。 The terrain level results from the value defined in the "Model Properties" section of the "General Data" window.
如有必要，用户可以通过图形方式或在“风洞”对话框中调整风洞的大小和位置（见章节 风洞）。 Make sure that enough space is provided on all sides of the model for the air to flow unimpeded.
洞口
如果您选择了“关闭洞口”选项（见第 网格设置），用户可以在 RWIND 3 模型中检查洞口或缝隙是否已被充分封闭。 If necessary, you can modify the settings in the image Edit Model dialog box of RWIND 3. Note that it will make a considerable difference for the analysis whether the air can flow through an opening or not.
Original Model
原始模型可以是在 RFEM 6/RSTAB 9 中创建的模型、从外部文件导入的模型或在 RWIND 3 的模型编辑器中创建的模型。 The outer surface of the model (outer shell) is the most important part for external aerodynamics. Before calculation, the outer surface of the model is divided into triangles. 模型表面的三角剖分是使用收缩包裹网格创建简化模型的基础，简化模型是模型周围空间中有限体积网格生成的基础。 The numerical calculation is performed in this finite volume mesh. Although one of the great advantages of RWIND 3 is the possibility of using a simplified model (shrink-wrapping), which eliminates most of the potential problems, still every numerical calculation should be preceded by at least a quick check of the correctness of the geometry of the original model.
Before starting the simulation, we should check the geometry of the original model to ensure that it is not too complex for our purpose and that it does not contain unnecessary parts of the model (for example, inner surfaces, partitions, and so on) that are not important for our numerical simulation (external aerodynamics). Internal surfaces in a closed model (closed volume) increase the computational requirements in terms of both data and time, and can lead to inaccuracies. The more complex the geometry, the more time should be spent on checking the original model mesh and generated finite volume mesh. 为此, Mesh Inspector tool is used.
Simplified Model
RWIND 3 features a "Simplified Model", which is created from the original RFEM 6 / RSTAB 9 model. 它是一个特殊的网格，用于定义模型边界（有关详细信息，请参见第 章计算网格和模型简化）。
You can display the simplified model as follows:
- Select the "Show Simplified Model" option in the panel.
- Select the "Simplified" option in the "View navigator" for the Model display.
The degree of simplification is controlled by the "Level of detail" specified in the "Edit Model" dialog box. Chapter "General" includes an example that shows the effects of this value on the "shrink-wrapping" process applied to the model. If the boundaries are not represented properly, you can adjust the level. When you click
in the
Edit Model
dialog box, you can immediately check the modifications and view the new simplified model. Note that a very detailed model will accordingly require more computational time.