在 RWIND 3 Pro 中可以对面应用渗透性。 关于渗透性的简要理论介绍，请参见章节 渗透性。 In RWIND 3 Pro, the permeability is modeled using a boundary condition, a prescribed pressure drop on defined surfaces. The pressure drop (pressure gradient) is given by Eq.:
|
Δp[Pa] |
Pressure drop |
|
μ[Pa.s] |
Dynamic viscosity of the fluid |
|
U[m/s] |
Velocity of the fluid |
|
D[1/m2] |
Darcy coefficient |
|
I[1/m] |
Inertial coefficient |
|
ρ[kg/m3] |
Density of the fluid |
|
L[m] |
Permeable media length in the flow direction |
where the coefficients D and I are defined as:
在章节 渗透性 中讨论的可渗透介质模型中，在 N‑S 方程右侧要求解渗透性的单元格重心处添加了一个源项。 Since RWIND 3 Pro only solves permeable surfaces (that is, relatively thin elements), the permeability is modeled using a cyclic boundary condition (porousBafflePressure) so far, prescribing the pressure gradient on the selected elements (patch). 有关更多详细信息，请参见 OpenFOAM 手册。 This is a computationally simple model and interesting results can be achieved in a short computation time. However, it has its limitations, for example, using the model for high pressure drop may not lead to convergence and results.
有关渗透性模型（porousBafflePressure）的更多具体信息，可在OpenFOAM-4.1手册中找到。
Permeability & Zones
在 RWIND 3 Pro 中，渗透性作为材料属性分配给选定的区域，见下面的图像。
In the "Edit Zone" dialog box, the "Material" section, click "Create new material..." or "Edit material...". A dialog box with permeability parameters appears.
Here, the permeability coefficients D, I, and the permeable surface length (thickness) L have to be defined. 有关如何推导和获取这些系数的介绍已在第 渗透性 章中描述。 More ideas and approaches to deriving the coefficients can also be found here:
Darcy-Forchheimer 计算器
One way to obtain the coefficient and model the permeability is described in the Knowledge Base Article on the Dlubal website.
After setting all coefficients and assigning zones to surfaces, the model with permeable surfaces is ready for calculation.
