UnSteady Boundary Conditions - Changing with time

April 11, 2005, 15:03

I want to simulate an inlet valve in an engine.

Therefore I have a pressure outlet at the valve. The pressure is changing with time, and is defined with a UDF (User-Defined-Function). This works...

However, I want to change the outlet boundary condition to a 'wall' when the valve is closed.

Docker

(I have been using a journal file, but at the moment it is not reading in proporly, if anyone knows the correct order of commands and syntax, for changing boundary conditions at time steps, that would be great!)

madhu31 · October 9, 2009, 14:49

hi i need ur udf file for pressure changing with time.because i have to simulate a flow for a pipe and i have write udf to determine pressure unsteadiness in pipe.

Zenith · October 24, 2009, 09:30

HI , I need ur UDF too.
I'm trying to do UDF about pressure profile.

help me please.

my e-mail :san_36c3@hotmail.com

Sergiu · July 13, 2011, 06:06

Quote:

Originally Posted by Zenith

HI , I need ur UDF too.
I'm trying to do UDF about pressure profile.

help me please.

my e-mail :san_36c3@hotmail.com

Hi Zenith,

I need also that UDF file, did you received from the collegues?
can u help me?

Nasos · July 14, 2011, 12:01

Hi,

I have to simulate the air flow and calculate the ventilation rate of a building under unsteady conditions. Since the air flow inside the building is dominated by the outside conditions (wind speed, wind velocity and air temperature), how can I solve the problem under unsteady conditions. I have experimental data for outside every 5 min. How can I set these data as boundary conditions?

Nasos

April 11, 2005, 15:03	UnSteady Boundary Conditions - Changing with time	#1
Docker Guest Posts: n/a	I want to simulate an inlet valve in an engine. Therefore I have a pressure outlet at the valve. The pressure is changing with time, and is defined with a UDF (User-Defined-Function). This works... However, I want to change the outlet boundary condition to a 'wall' when the valve is closed. Docker (I have been using a journal file, but at the moment it is not reading in proporly, if anyone knows the correct order of commands and syntax, for changing boundary conditions at time steps, that would be great!)

October 9, 2009, 14:49	help me creating a udf for pressure varies with time	#2
madhu31 New Member madhu sudhan Join Date: Oct 2009 Posts: 1 Rep Power: 0	hi i need ur udf file for pressure changing with time.because i have to simulate a flow for a pipe and i have write udf to determine pressure unsteadiness in pipe.

October 24, 2009, 09:30		#3
Zenith New Member Join Date: Oct 2009 Posts: 4 Rep Power: 17	HI , I need ur UDF too. I'm trying to do UDF about pressure profile. help me please. my e-mail :san_36c3@hotmail.com Last edited by Zenith; October 24, 2009 at 10:38.

July 14, 2011, 12:01	air flow and unsteady boundary conditions	#5
Nasos New Member Nasos Join Date: Mar 2010 Posts: 2 Rep Power: 0	Hi, I have to simulate the air flow and calculate the ventilation rate of a building under unsteady conditions. Since the air flow inside the building is dominated by the outside conditions (wind speed, wind velocity and air temperature), how can I solve the problem under unsteady conditions. I have experimental data for outside every 5 min. How can I set these data as boundary conditions? Nasos

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Implementation of boundary conditions for FVM	Tom	Main CFD Forum	7	August 26, 2014 06:58
Water subcooled boiling	Attesz	CFX	7	January 5, 2013 04:32
CFX does not continue	Shafiul	CFX	10	February 17, 2011 08:57
air bubble is disappear increasing time using vof	xujjun	CFX	9	June 9, 2009 08:59
Boundary conditions?	Tom	Main CFD Forum	0	November 5, 2002 02:54