5th-order scheme

aynjust · December 3, 2013, 09:31

Dear Foamer, I am new to OpenFOAM, so my qestion may be slliy. I want to know what are the 5th-order scheme in the interpolationScheme. thanks

RodriguezFatz · December 4, 2013, 04:19

I don't think there are any. This would be incredibly complicated to code for a unstructured solver. Also, all other integrals are 2nd order anyway ("midpoint-rule") - so why would someone want higher accuracy for some single value?

aynjust · December 4, 2013, 07:41

Quote:

Originally Posted by RodriguezFatz

I don't think there are any. This would be incredibly complicated to code for a unstructured solver. Also, all other integrals are 2nd order anyway ("midpoint-rule") - so why would someone want higher accuracy for some single value?

I want to take advantage of SA - DDES model calculation under different attack angles of aerodynamic parameters, so you need to use high precision of interpolation

aynjust · December 4, 2013, 07:49

Quote:

Originally Posted by RodriguezFatz

I don't think there are any. This would be incredibly complicated to code for a unstructured solver. Also, all other integrals are 2nd order anyway ("midpoint-rule") - so why would someone want higher accuracy for some single value?

I want to take advantage of SA - DDES model calculating the aerodynamic parameters of the delta wing under different Angle of attack, so you need to use high precision of interpolation

RodriguezFatz · December 4, 2013, 07:54

I don't get this. Integrals are done with the midpoint rule so they are second order accurate, if you know the midpoint value with 2nd order accuracy. They are still 2nd order, if you know the midpoint value with 5th order, right? So why would you implement that in OpenFoam?

aynjust · December 4, 2013, 22:09

Quote:

Originally Posted by RodriguezFatz

I don't get this. Integrals are done with the midpoint rule so they are second order accurate, if you know the midpoint value with 2nd order accuracy. They are still 2nd order, if you know the midpoint value with 5th order, right? So why would you implement that in OpenFoam?

In divScheme, how will the divergence term up to 5th-order accuracy?

RodriguezFatz · December 5, 2013, 02:29

It seems that you don't understand what I tried to say, so I will try again...
The "divScheme" will determine the way the value in the middle of the face is calculated. This value is used to calculate the integral over the face. The integral will be 2nd order, even if you know the midpoint value with 10th order. So what you ask is useless.

Tushar@cfd · December 5, 2013, 05:04

Quote:

Originally Posted by aynjust

Dear Foamer, I am new to OpenFOAM, so my qestion may be slliy. I want to know what are the 5th-order scheme in the interpolationScheme. thanks

Hello Ayun,

I don't think so it is easy task for a newbie.

Anyways, have a look to the following web-link:

HTML Code:

http://www.cfd-online.com/Forums/openfoam/94447-high-order-convective-schemes.html

I hope with this you will clear your doubts.

December 3, 2013, 09:31	5th-order scheme	#1
aynjust New Member aiyu Join Date: Jul 2013 Posts: 8 Rep Power: 14	Dear Foamer, I am new to OpenFOAM, so my qestion may be slliy. I want to know what are the 5th-order scheme in the interpolationScheme. thanks

December 4, 2013, 04:19		#2
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 28	I don't think there are any. This would be incredibly complicated to code for a unstructured solver. Also, all other integrals are 2nd order anyway ("midpoint-rule") - so why would someone want higher accuracy for some single value? __________________ The skeleton ran out of shampoo in the shower.

December 4, 2013, 07:54		#5
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 28	I don't get this. Integrals are done with the midpoint rule so they are second order accurate, if you know the midpoint value with 2nd order accuracy. They are still 2nd order, if you know the midpoint value with 5th order, right? So why would you implement that in OpenFoam? __________________ The skeleton ran out of shampoo in the shower.

December 5, 2013, 02:29		#7
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 28	It seems that you don't understand what I tried to say, so I will try again... The "divScheme" will determine the way the value in the middle of the face is calculated. This value is used to calculate the integral over the face. The integral will be 2nd order, even if you know the midpoint value with 10th order. So what you ask is useless. __________________ The skeleton ran out of shampoo in the shower.

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