💥💥💥 What is porous jump boundary conditions and how to define it in Ansys Fluent ?

 Porous jump boundary conditions are used to model a thin membrane that has known velocity (pressure-drop) characteristics. It is a 1D simplification of the porous media model available for cell zones in Ansys Fluent¹. Examples of uses for the porous jump condition include modeling pressure drops through screens and filters, and modeling radiators when you are not concerned with heat transfer¹.

To define a porous jump boundary condition in Ansys Fluent, you need to follow these steps¹:

1. Identify the porous-jump zone. This is a type of internal face zone that represents the interface between cells, rather than a cell zone. You can use the Boundary Conditions task page to change the appropriate face zone to a porous-jump zone.
2. Set the Face Permeability of the medium. This is the coefficient that determines the pressure drop across the porous jump due to viscous effects. You can use different methods to calculate or estimate the face permeability, depending on the available data and assumptions.
3. Set the Porous Medium Thickness. This is the thickness of the porous medium that is used to calculate the pressure drop across the porous jump due to inertial effects. You can use a small value that is representative of your problem, such as 1e-5 m.
4. Set the Pressure-Jump Coefficient. This is the coefficient that determines the pressure drop across the porous jump due to inertial effects. You can use different methods to calculate or estimate the pressure-jump coefficient, depending on the available data and assumptions.
5. Define the discrete phase boundary condition for the porous jump (for discrete phase calculations). This is the option that specifies what happens to the particles that encounter the porous jump. You can choose to trap, escape, reflect, or rebound them.

How to fdefine porous jump in console  - Ansys Fluent ?

To enter these inputs in the console, you can use the following commands:

/define/boundary-conditions/porous-jump
zone-name <name-of-the-zone>
face-permeability <value-of-face-permeability>
porous-medium-thickness <value-of-porous-medium-thickness>
pressure-jump-coefficient <value-of-pressure-jump-coefficient>
discrete-phase-boundary-condition <trap|escape|reflect|rebound>

For example, if you want to add a porous jump boundary condition for a zone named “filter” with a face permeability of 1e-10 m^2, a porous medium thickness of 1e-5 m, a pressure-jump coefficient of 0.5 kg/m^3, and a discrete phase boundary condition of trap, you can type:

/define/boundary-conditions/porous-jump
zone-name filter
face-permeability 1e-10
porous-medium-thickness 1e-5
pressure-jump-coefficient 0.5
discrete-phase-boundary-condition trap

You can find more information about the porous jump model and its inputs in this web search result. I hope this answer is helpful for you.