Capturing Large Variations using FINITE DIFFERENCE

August 20, 1999, 07:32

Hello "Gurus",

I am doing a 1-D flow using finite difference in Conservation forms. There are quite a large variations in density and velocity expected towards the END side. And boundary values are calculated using LINEAR EXTRAPOLATION.

The program develops HUGE VALUES of density and velocity and goes unstable towards the BOUNDARY END-SIDE.

Other grid points away from boundary are OKEY. Shall I increase the grid-size or REDUCE the time-step?

Can anybody help?

August 20, 1999, 13:21

(1). What is the problem you are trying to solve? (2). Based on your description, it is hopeless. You have both the accuracy problem and the stability problem. (3). It is a good idea to look for a working method first.

August 20, 1999, 07:32	Capturing Large Variations using FINITE DIFFERENCE	#1
Yogesh Talekar Guest Posts: n/a	Hello "Gurus", I am doing a 1-D flow using finite difference in Conservation forms. There are quite a large variations in density and velocity expected towards the END side. And boundary values are calculated using LINEAR EXTRAPOLATION. The program develops HUGE VALUES of density and velocity and goes unstable towards the BOUNDARY END-SIDE. Other grid points away from boundary are OKEY. Shall I increase the grid-size or REDUCE the time-step? Can anybody help?

August 20, 1999, 13:21	Re: Capturing Large Variations using FINITE DIFFERENCE	#2
John C. Chien Guest Posts: n/a	(1). What is the problem you are trying to solve? (2). Based on your description, it is hopeless. You have both the accuracy problem and the stability problem. (3). It is a good idea to look for a working method first.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Finite element vs. finite difference	Francisco Saldarriaga	Main CFD Forum	23	December 17, 2014 09:21
natural convection induced by radiation. large temperature difference!	uncle_salty	FLUENT	0	February 3, 2010 12:57
Finite difference can be non-conservative?	gregmason	Main CFD Forum	2	July 8, 2009 12:53
Fininte difference and Finite element Technique	Mahendra Singh Mehra	FLUENT	3	December 23, 2005 00:49
finite difference method for navier-stokes problem	dallybird	Main CFD Forum	5	February 17, 2003 23:00