CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS

Interaction between open channel flow and porous flow

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   June 8, 2020, 12:42
Default Interaction between open channel flow and porous flow
New Member
Join Date: Mar 2013
Location: Nebraska
Posts: 19
Rep Power: 9
narendrapatel111 is on a distinguished road
##FLUENT. I have two infinitely long and wide flow zones- (1) free flow zone and (2) porous flow zone and both zones make an interface so that water can flow from one zone to other zone. Ideally itís 2D problem but I donít get mass conservation (inflow ≠ outflow) in 2D simulation and solution is unstable so I am solving it as 3D problem and assigning both side walls (span wise direction) as symmetric BC. (Since flow is 2D on symmetric surface and I know as we move away from symmetric surface, there will be small velocity component in span wise direction as I am using 3D solver. I am interested for velocity component in streamwise direction only as other two components are negligible). I also assign top as symmetric BC. (Let me know if you need more explanation on this).
I have created geometry horizontal and to consider slope of the bed, I calculate gravity components in streamwise and vertical direction. I am interested for flow in both zones together. For STEADY UNIFORM flow,
1) Can I assign two periodic boundary conditions as shown in figure? Is interface an issue? I have same pressure drop between inlets and outlets for both zones.

2) Assume it's case for flow in river with sand bed and slope is only in length wise direction. For Periodic boundary conditions inputs, I calculate pressure drop using slope in river (rho*g*tan(theta)). Now should I still activate gravity in both vertical and flow direction? Or should I make pressure drop zero and activate gravity?

3) Interface is very smooth, is there any way we can make it rough so it will represent rough sand (diameter around 3mm)?

4) FLUENT always uses bottom wall of porous bed to calculate Y+ or Y* but as porosity decreases, the interface starts behaving like a wall but Fluent wouldnít consider that. I want to generate log profile in free flow region when porosity is less then around 0.25. In natural porous river bed, log profile is observed (with slip velocity at interface) even if porosity is as high as around 0.35. Is it possible to generate the log profile using software?
Attached Images
File Type: png Periodic.png (161.3 KB, 3 views)
narendrapatel111 is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Open channel, Gravity driven flow over and through a porous bed narendrapatel111 FLUENT 0 June 8, 2020 05:14
Open channel flow over porous bed, interface roughness narendrapatel111 Fluent Multiphase 0 July 5, 2017 23:17
Flow through a simple porous rectangular channel kinni CFD Freelancers 3 October 21, 2016 11:05
Strange behaviour: Ethanol solution flow on channel with interface to porous domain khariel CFX 6 December 11, 2014 18:08
Open Channel Flow Boundary Conditions TWaung STAR-CCM+ 2 October 7, 2011 01:37

All times are GMT -4. The time now is 23:03.