Ahmed body: questions about reference area and forces

sandyy235 · October 18, 2016, 04:37

I am simulating Ahmed body and am confused whether for calculating the coefficient of drag ,i should use the frontal area or the whole area of the Ahmed body.

Am refering to the motorbike tutorial ,there the whole area of the bike is 12.1486 calculated from paraview,but the Aref is taken to be 0.75.

Can anyone please suggest.

sandyy235 · October 18, 2016, 05:06

How Aref is calculated in Ahmed body in Openfoam ?

danielbanos10 · October 18, 2016, 06:23

In "forceCoeffs" you define your area for the calculation of drag, for example:

"AreaRef 0.03141;"

sandyy235 · October 21, 2016, 09:18

hi,can you please tell me, In Openfoam for the Ahmed body we are giving the Aref as 0.112 ,can you please suggest whether the Openfoam is taking the same area for calculating the lift coefficient ? Since the area which i have mentioned is the projected area in the X direction and we are not taking Aref in the y direction nowhere in Openfoam

wyldckat · October 30, 2016, 09:50

Quick request @sandyy235: Please provide more details on how you are setting up these parameters.

October 18, 2016, 04:37	Ahmed body: questions about reference area and forces	#1
sandyy235 New Member Sandyy Join Date: Oct 2015 Posts: 20 Rep Power: 11	I am simulating Ahmed body and am confused whether for calculating the coefficient of drag ,i should use the frontal area or the whole area of the Ahmed body. Am refering to the motorbike tutorial ,there the whole area of the bike is 12.1486 calculated from paraview,but the Aref is taken to be 0.75. Can anyone please suggest.

October 18, 2016, 05:06	Ahmed body: questions about reference area and forces	#2
sandyy235 New Member Sandyy Join Date: Oct 2015 Posts: 20 Rep Power: 11	How Aref is calculated in Ahmed body in Openfoam ?

October 30, 2016, 09:50		#5
wyldckat Retired Super Moderator Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 10,982 Blog Entries: 45 Rep Power: 128	Quick request @sandyy235: Please provide more details on how you are setting up these parameters. __________________ OpenFOAM: FAQ \| Getting started Forum: How to get help, to post code/output and forum guide Read this before sending me PM

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October 18, 2016, 06:23		#3
danielbanos10 New Member Join Date: Jun 2016 Location: Malaga, Spain Posts: 15 Rep Power: 10	In "forceCoeffs" you define your area for the calculation of drag, for example: "AreaRef 0.03141;"

October 21, 2016, 09:18		#4
sandyy235 New Member Sandyy Join Date: Oct 2015 Posts: 20 Rep Power: 11	hi,can you please tell me, In Openfoam for the Ahmed body we are giving the Aref as 0.112 ,can you please suggest whether the Openfoam is taking the same area for calculating the lift coefficient ? Since the area which i have mentioned is the projected area in the X direction and we are not taking Aref in the y direction nowhere in Openfoam