Normal to boundary velocity

alberto · January 21, 2006, 19:39

I have to model a pipe with a circular corona inlet all around the pipe circumference.

I have to specify a velocity normal to this boundary. How can I do it in OpenFOAM?

Thanks in advance
Alberto

mattijs · January 23, 2006, 04:30

surfaceNormalFixedValue (in OpenFOAM/lnInclude/surfaceNormalFixedValueFvPatchField.H)

needs a 'refValue' entry which is the outwards pointing velocity (so negative for inflow)

alberto · January 23, 2006, 17:30

Thanks!

braennstroem · June 21, 2007, 10:12

Hi,

it seems that I have a similar problem... I would like to calculate a hvac duct and have to set the inlet velocity normal to the boundary. Unfortunately, I do not understand, what Mattijs wrote as a hint!?

Regards!
Fabian

alberto · June 21, 2007, 14:11

If the boundary is flat, use fixedValue and specify the appropriate components of the velocity.

If it's not flat You can use:

type surfaceNormalFixedValue;
refValue uniform Umag;

As Mattijs said, if you want your flow to enter your domain, Umag has to be negative.

Regards,
Alberto

June 22, 2007, 02:39

Hi,

On a similar note, if I were to simulate boundary layer suction or blowing, would it be valid to use an ordinary wall boundary condition with a (strictly) normal velocity specified (either by using fixedValue or surfaceNormalFixedValue), or would a specialized boundary condition need to be build?

Also, could, for moderate normal velocities, a wall function still be used? Or will a low-Re turbulence model be required?

best regards,
Roland

braennstroem · July 3, 2007, 08:16

Hi Alberto,

thanks for the help!

Regards!
Fabian

January 21, 2006, 19:39	I have to model a pipe with a	#1
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	I have to model a pipe with a circular corona inlet all around the pipe circumference. I have to specify a velocity normal to this boundary. How can I do it in OpenFOAM? Thanks in advance Alberto __________________ Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using.

January 23, 2006, 04:30	surfaceNormalFixedValue (in Op	#2
mattijs Senior Member Mattijs Janssens Join Date: Mar 2009 Posts: 1,419 Rep Power: 26	surfaceNormalFixedValue (in OpenFOAM/lnInclude/surfaceNormalFixedValueFvPatchField.H) needs a 'refValue' entry which is the outwards pointing velocity (so negative for inflow) Rojj and RjwV like this.

January 23, 2006, 17:30	Thanks!	#3
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	Thanks! __________________ Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using.

June 21, 2007, 10:12	Hi, it seems that I have a	#4
braennstroem Senior Member Fabian Braennstroem Join Date: Mar 2009 Posts: 407 Rep Power: 19	Hi, it seems that I have a similar problem... I would like to calculate a hvac duct and have to set the inlet velocity normal to the boundary. Unfortunately, I do not understand, what Mattijs wrote as a hint!? Regards! Fabian

June 21, 2007, 14:11	If the boundary is flat, use f	#5
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	If the boundary is flat, use fixedValue and specify the appropriate components of the velocity. If it's not flat You can use: type surfaceNormalFixedValue; refValue uniform Umag; As Mattijs said, if you want your flow to enter your domain, Umag has to be negative. Regards, Alberto prashantsonakar and RjwV like this. __________________ Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using.

June 22, 2007, 02:39	Hi, On a similar note, if I	#6
rswbroers Guest Posts: n/a	Hi, On a similar note, if I were to simulate boundary layer suction or blowing, would it be valid to use an ordinary wall boundary condition with a (strictly) normal velocity specified (either by using fixedValue or surfaceNormalFixedValue), or would a specialized boundary condition need to be build? Also, could, for moderate normal velocities, a wall function still be used? Or will a low-Re turbulence model be required? best regards, Roland

July 3, 2007, 08:16	Hi Alberto, thanks for the	#7
braennstroem Senior Member Fabian Braennstroem Join Date: Mar 2009 Posts: 407 Rep Power: 19	Hi Alberto, thanks for the help! Regards! Fabian

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
WALL normal velocity	Luca	Main CFD Forum	1	October 8, 2014 05:21
Opening BC: Normal to boundary	Jan Ramboer	CFX	3	September 21, 2007 15:06
velocity normal to the surface	srinivas	Siemens	1	May 30, 2007 02:03
Velocity gradient normal to a wall	ap	FLUENT	0	July 26, 2004 08:32
Shear and normal stress on a boundary	Fing	CFX	2	May 27, 2004 01:47