The Navier stokes equations

Mirza · August 21, 2016, 14:15

Hi!
I am new here and in the world of CFD
i have questions please
1- why we use often the vorticity-velocity formulation than the primitive one (in 2D)

2-I read that the uwpind sheme is more accurate for solving the primitive formulation of NSeqs. why?

thank you
Best regards

FMDenaro · August 22, 2016, 04:18

Quote:

Originally Posted by Mirza

Hi!
I am new here and in the world of CFD
i have questions please
1- why we use often the vorticity-velocity formulation than the primitive one (in 2D)

2-I read that the uwpind sheme is more accurate for solving the primitive formulation of NSeqs. why?

thank you
Best regards

1) Actually, I don't see such formulation very often...the stream function-vorticity is often used for 2d, laminar flow because you solve only 1 parabolic equation and the elliptic equation for the stream function has boundary conditions that make faster the convergence than the pressure equation.

2) Your statement is not correct. Accuracy depends on the type of the discretization and is not related to upwinding.

Mirza · August 22, 2016, 08:27

1- yes i wanted to say stream-vorticity, thank you.

2- the same when we have a big Re (the convection term dominated)??

Mirza · August 24, 2016, 13:04

any help please?

also could you give me some books or paper to read for beginners?
thank you

best regards

FMDenaro · August 24, 2016, 14:31

you can find the main titles in this forum, for example the book of Peric & Ferziger

The_Provost · August 25, 2016, 00:57

Introduction to Computational Fluid Dynamics by John Anderson is a classic beginner's text book.

davidwilcox · August 30, 2016, 22:21

To clear your doubts pertaining to the upwind scheme, try looking up the peclet number.

August 21, 2016, 14:15	The Navier stokes equations	#1
Mirza New Member Maryam Mirza Join Date: Aug 2016 Posts: 12 Rep Power: 10	Hi! I am new here and in the world of CFD i have questions please 1- why we use often the vorticity-velocity formulation than the primitive one (in 2D) 2-I read that the uwpind sheme is more accurate for solving the primitive formulation of NSeqs. why? thank you Best regards

August 24, 2016, 14:31		#5
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,897 Rep Power: 73	you can find the main titles in this forum, for example the book of Peric & Ferziger Mirza likes this.

August 25, 2016, 00:57		#6
The_Provost New Member The_Provost Join Date: Sep 2014 Location: USA Posts: 15 Rep Power: 12	Introduction to Computational Fluid Dynamics by John Anderson is a classic beginner's text book. Ichenial Mohammed Marouan likes this.

August 30, 2016, 22:21		#7
davidwilcox Senior Member david Join Date: Oct 2012 Posts: 142 Rep Power: 14	To clear your doubts pertaining to the upwind scheme, try looking up the peclet number. Mirza likes this.

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August 22, 2016, 08:27		#3
Mirza New Member Maryam Mirza Join Date: Aug 2016 Posts: 12 Rep Power: 10	1- yes i wanted to say stream-vorticity, thank you. 2- the same when we have a big Re (the convection term dominated)??

August 24, 2016, 13:04		#4
Mirza New Member Maryam Mirza Join Date: Aug 2016 Posts: 12 Rep Power: 10	any help please? also could you give me some books or paper to read for beginners? thank you best regards