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

Two bodies in same fluid but different velocities

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

LinkBack Thread Tools Search this Thread Display Modes
Old   December 11, 2020, 06:54
Default Two bodies in same fluid but different velocities
New Member
Join Date: Nov 2012
Posts: 18
Rep Power: 12
averis007 is on a distinguished road
I wish to simulate a flow in which two solid bodies move at different but constant speeds (v1 and v2) through the same fluid. I'm using overset and dynamic mesh but I'm struggling with setting up the case correctly.

For example, if there was only one body (b1) and I wanted to move it through the fluid at v1 velocity, I would just give a farfield boundary condition to my domain with velocity v1 and that'll simulate a flow past the body at v1 velocity. Using standard sign conventions it'll mean a flow going from left to right over the body.

Now that i have two bodies moving at different velocities, i can't give any farfield velocity. Hence I have to move the two component zones containing the bodies, and the bodies themselves with velocity -v1 and -v2 respectively. that is the bodies will be moving from right to left now in an almost stationary background domain (given a velocity about ~1m/s just to initialize).

The problem is that no matter how I try to define the motion of the bodies, whether with UDF or with profile files, since they are moved with a negative speed, it creates a negative velocity region in front of the body. that is effectively creating a huge bluff body instead of a smooth aerodynamic body that I'm actually simulating for.

If it helps, what I'm actually trying to simulate is the effect of the wake of a slow moving but large body on the motion of the faster but smaller body behind it.

If somebody who has worked on something similar, or knows how to set up a case with relative motions of bodies can just give some pointers here, it'll be a great help to me.
averis007 is offline   Reply With Quote


dynamic mesh, mesh motion, overset mesh, relative motion

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
[solids4Foam] How to calculate drag coeff when using solids4Foam amuzeshi OpenFOAM CC Toolkits for Fluid-Structure Interaction 15 November 7, 2019 12:50
Physics of an incompressible fluid Jonas Holdeman Main CFD Forum 87 April 22, 2019 10:40
Difficulty in calculating angular velocity of Savonius turbine simulation alfaruk CFX 14 March 17, 2017 06:08
My Revised "Time Vs Energy" Article For Review Abhi Main CFD Forum 2 July 9, 2002 09:08
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11

All times are GMT -4. The time now is 17:14.