Dear Neks, I have modified the turbChannel example (available in v17.0) to a WRLES flat plate test case and validated it against DNS data. One step further, I am now imposing traction boundary condition on the wall, i.e tauw (TRX,TRZ) and computing the wall shear stress thanks to torque_calc routine. The computed wall shear stress corresponds to the one I am imposing. However the fluid accelerates at the wall and never converges to a value. 1. The wall shear stress in correct but the velocity increases over time. How can this be possible ? 2. Are you aware of the formalism surrounding traction boundary condition in the discrete equations ? Sincerely, Armand. -- *Armand Shams* Master Thesis Intern Département aérodynamique, aéroélasticité, acoustique MSAT Tél: +33 6 99 51 15 84 ONERA - The French Aerospace Lab - Centre de Meudon 8, rue des Vertugadins - 92190 MEUDON Nous suivre sur : www.onera.fr <https://www.onera.fr> | Twitter <http://www.twitter.com/@onera_fr> | LinkedIn <http://www.linkedin.com/company/onera> | Facebook <http://www.facebook.fr/thefrenchaerospacelab> Avertissement/disclaimer https://www.onera.fr/en/emails-terms