How to find the coordinates of center of pressure

Alexey

Hello. I have some problems with determination of coordinates of center of pressure in the conical model which is moving in the air flow with angle of attack equal to 0 degrees. From the beginning I have several models. The value of velocity is constant in these models and the angle of attack changes from 5 up to 0 degrees. I calculated the center of pressure in cases with non-zero angle of attack by the following method: Z= Sum(Moments)/Sum(SFTX) i.e. the sum of the Moments in every cells on the models surface was divided on the sum of the Total force in these cells in corresponding direction.

But now I don't have the normal component of the Total force, therefore I can't calculate the Moment.

Only one idea is observed: create a charts Z(angel) and continue they up to the 0 degree. But I can't explain this method. So I have two questions: 1. Was I right when I calculated the coordinates of the center of pressure in the cases with angle of attack NOT equal to 0 by described way. 2. How can I find the center of pressure in the case when angle of pressure is equal to 0.

Best regards, Alexey.