June 7, 2021 at 6:21 amVanesaSubscriber
I have done a 3D simulation of a Boeing 737 wing (half-model) at a particular flow condition. I did report definitions of Lift and CL which were obtained as 835.26 N and 0.638 respectively.
Now I want to verify the lift obtained using pressure distribution. However when I am computing the value of 'Integral of static pressure over wing surface' it is giving a value of -1703.45 N.
Why is the lift value different? Or where am I going wrong? Also, how do I know along which axis is the integral of static pressure over wing (which is a force with a negative sign) directed?
Thanks in advance.June 7, 2021 at 10:41 amRobAnsys EmployeeLift, drag, force, drag coefficient etc are defined in the documentation. If you integrate the static pressure you'll get the sign and value relative to the operating pressure so it may or may not be negative. If the wing is working the upper surface may be more negative than the lower surface.
June 9, 2021 at 12:08 pmVanesaSubscriberDefinition of lift (2D): Total lift is the integral of the pressure, in the direction perpendicular to the farfield flow, over the airfoil surface.
For a given flow conditions of density, velocity, operating pressure, shouldn't the outcome of lift (given as report definition) and the outcome of computed value of 'integral of static pressure over wing surface' be equal?
The computed value of integral of pressure over the wing is always around 2 times the lift which is computed. Why is it so? I am not able to understand why this mismatch is happening. Please clarify.
June 10, 2021 at 5:37 amJune 10, 2021 at 3:31 pmDrAmineAnsys EmployeeYou need to build the areaInt in X, Y and Z Directions. You can use Sum reduction function and multiply the Static Pressure with the Facet Area in the appropriate direction. You get a vector and you can get its magnitude or scalar product with the direction to get the right magnitude in the requested direction. Integral of pressure is WRONG.
June 11, 2021 at 7:25 amVanesaSubscriberOkay. Thank you very much for showing the path. Thank you.
June 11, 2021 at 9:43 amDrAmineAnsys EmployeeWelcome!
June 11, 2021 at 9:43 amDrAmineAnsys Employee:)
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