Analyzing surface for water flow

[reedybY4SLV]

Hello, I am new to this program I have some experience with rhino CFD and butterfly but still novice with CFD's in general. I am trying to analyze a model I made using Rhino/Grasshopper to see how water would move/accelerate across it. This is my current work flow, is there anything I am/am not doing that would give me better results?

1. Load model into CFD and set dimensions for exterior volume then surface wrap at 3000-5000 resolution

2. Apply solid (dried peat soil) material to model

3. Apply fluid (water) material to exterior volume

4. Set boundary conditions on model (slip/symmetry)

5. Set boundary conditions on exterior volume (inlet = velocity = constant @ .1 m/s) (outlet = pressure @ 0 pa)

6. Auto size mesh 

7. Set solver setting, mostly maintaining defaults, Advection = ADV 5; Flow (Incompressible) = True; Turbulence = k-epsilon w/ Turb/Lam ratio  @ 100; Iterations = 200

Here is a screenshot of the rhino model.The goal of the model is creating a mesh that can help optimize water movement across a landscape, so I'm trying to get as close to how water flow down a hillside. The slope is relatively gradual and the model dimensions are X = 80in Y = 80 in and Z = ~28"

Any help would be appreciated, thanks!

[marwan_azzam]

Hello @reedybY4SLV ,

I would not do #4 above if you mean you applied Slip/Symmetry boundary conditions (BC) on the surface of the solid.

Where the fluid touches the solid the fluid should have zero velocity so a Slip/Symmetry BC is not applicable.

Marwan

[reedybY4SLV]

Ok thank you, I will try that. The reason I did that is because some of the vectors were penetrating into the volume of the solid and a slip boundaries prevents that. Is there another way I can prevent that from happening?

[marwan_azzam]

Fluid will not penetrate into the solid no matter which BCs you define.

Marwan