Varying Lift Coefficients
 

Hello everyone,

I'm facing a problem with my ANSYS FLUENT simulations regarding the calculation of lift coefficients for aircraft elevator and elevator trim tab. Whenever I adjust the dimensions of the trim tab, I notice significant fluctuations in both the trim tab and elevator lift coefficients, the latter which should most definitely not happen.

Despite following methodologies that used to work before, I can't seem to achieve any consistent results. Maybe I'm going about this in a wrong way, I'd love to know how to accurately make lift calculations for every seperate part (stabilizer, elevator, trim tab) and get consistent results for my simulations or how to calculate moments, because I'm trying to find the change of the hinge moment for elevator using trim tabs. If anyone has encountered similar issues or has any insights on this, I'd greatly appreciate your guidance.

Thanks for your help in advance.

These are my calculation results (cl_e and l_e being elevator coef and lift and cl_t and l_t being trim tab coef and lift):

First
cl_e-op -1.9281960608e-02 []
cl_t-op 3.1437584034e-02 []
l_e-op -2.3816207438e+03 [N]
l_t-op 1.4113290342e+02 [N]

Second (smaller trim tab, same elevator size and conditions)
cl_e-op -4.4154678560e-02 []
cl_t-op 1.8855157262e-02 []
l_e-op -6.5873093253e+03 [N]
l_t-op 5.4930372883e+01 [N]