flow in cylinder

nhosseini · September 15, 2012, 04:48

Hi every body!

I would be so thankful if any body could help me about the physical solution of

in-compressible flow in cylinder.

a flow is at rest in the initial and suddenly a piston at left end of cylinder starts

to move with constant speed of Vpiston, what would be velocity and pressure values in cylinder?

Jonas Holdeman · September 15, 2012, 10:25

I would expect that the entire column of fluid would instantly start moving with the piston at a velocity Vpiston (because of incompressibility) and a slug profile. Over time a fully-developed profile would develop ahead of the piston. Look at the problem in the frame of the piston. Then the cylinder would start moving toward the piston with a velocity -Vpiston.

nhosseini · September 15, 2012, 12:43

it seems that your comment is correct, but when I want to solve it numerically with control volume scheme it takes time to reach the constant velocity, and it doesn't instantly moves to answer, I would be thankful if you could help me

September 15, 2012, 04:48	flow in cylinder	#1
nhosseini New Member SNH Join Date: Dec 2011 Posts: 8 Rep Power: 14	Hi every body! I would be so thankful if any body could help me about the physical solution of in-compressible flow in cylinder. a flow is at rest in the initial and suddenly a piston at left end of cylinder starts to move with constant speed of Vpiston, what would be velocity and pressure values in cylinder?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
benchmark: flow over a circular cylinder	goodegg	Main CFD Forum	12	January 22, 2013 12:47
1 Was FSI for a flow over a cylinder	vmlxb6	CFX	17	May 16, 2011 03:29
Moving a Cylinder in cross flow after solving Dynamics equations of motion	maruthamuthu_venkatraman	OpenFOAM	1	November 19, 2009 14:55
Flow over a flat plate & Flow over a cylinder	cfdxue	Main CFD Forum	0	November 27, 2007 00:26
Flow over a cylinder	Anna	Main CFD Forum	9	March 24, 2006 15:32

September 15, 2012, 10:25		#2
Jonas Holdeman Senior Member Jonas T. Holdeman, Jr. Join Date: Mar 2009 Location: Knoxville, Tennessee Posts: 128 Rep Power: 18	I would expect that the entire column of fluid would instantly start moving with the piston at a velocity Vpiston (because of incompressibility) and a slug profile. Over time a fully-developed profile would develop ahead of the piston. Look at the problem in the frame of the piston. Then the cylinder would start moving toward the piston with a velocity -Vpiston.

September 15, 2012, 12:43		#3
nhosseini New Member SNH Join Date: Dec 2011 Posts: 8 Rep Power: 14	it seems that your comment is correct, but when I want to solve it numerically with control volume scheme it takes time to reach the constant velocity, and it doesn't instantly moves to answer, I would be thankful if you could help me