Partial slip wall: velocity gradient equation

[Fabio.Dioguardi]

Hi all,

I have a doubt on how the velocity of the phase is treated near the wall when using the partial slip wall. According to the manual (https://mfix.netl.doe.gov/doc/mfix/19.1.4/reference/boundary_condition.html), this equation is solved:
dv/dn + hw (v - vw) = 0, where n is the normal pointing from the fluid into the wall
Can you please confirm this? My doubt arose by looking at the source code (in particular, e.g., source_u_s.f) it looks like the following equation is solved instead: dv/dn + hw* vw = 0, which leads to a linear velocity profile instead.

Thanks
Fabio

[gaoxi]

see the attached figure for more explanation.

[mohsenclick]

I have posted a question and I would repeat it here… I want to use Mixed wall to implement the No-slip for fluid and Partial slip for the solids using TFM. But the problem is that the Jackson and Johnson Boundary condition is disabled under solids partial slip??? How can I activate it??? Also what is the Transfer coefficient in momemntum boundary condition of partial slip???

[gaoxi]

You can try the .mfix file posted in the following post.

Wall BC for TFM simulation

Dear MFIX community, I am simulating a pseudo 2D GAS-SOLID fluidized bed using MFIX-TFM 19.3.0 GUI. I have noticed a discrepancy when setting the BCs for the gas and solid phases. Ideally I would like the gas phase to be ‘NSW’ and for the solid phase ‘PSW’. However when I set the NSW for the gas phase, the same BC is duplicated for the solid phase and vice-versa. How can I go about this? I have attached a MFX file for my case sscp.mfx (29.6 KB)