Analysis of G\"ortler Vortices Spanwise Wavelenght Influence in Heat Transfer Rates

The centrifugal instability mechanism in boundary layers flows over concave surfaces is responsible for the development of streamwise counter-rotating vortices, known as G\"ortler vortices. These Vortices create two regions in the spanwise direction, the upwash and downwash regions. The downwash region is responsible to compress the boundary layer towards the wall, increasing drag and heat transfer rates. The upwash region does the opposite. In the nonlinear development of the G\"ortler vortices the upwash region becomes narrow, and the average drag and heat transfer rate is higher than that for a Blasius boundary layer. In the present research, using a Spatial Direct Numerical Simulation, it is analyzed the influence of the G\"ortler Vortices spanwise wavelength in heat transfer rates. Different wavelengths are analyzed and compared with experiments.\footnote {L. Momayez, P. Dupont and H. Peerhossaini, Int J Therm Sci, 43, 753--760 (2004)} The results show that steady G\"ortler flow can reach heat transfer rates higher than the turbulent values, even without introducing secondary instabilities.