Growing Turbulent Spot in Plane-Couette Flow and Dissimilarity Analysis Between Heat and Momentum Transfers

Abstract

Direct numerical simulations (DNSs) were performed to study the dissimilarity between the heat and momentum transfer of turbulent spot structures developing in a laminar plane Couette flow. The turbulent spot was generated by pair vortices, and the Reynolds and Prandtl numbers were 450 and unity, respectively. Three types of computational domains were examined to reveal the effect of the spot development on the dissimilarity. As a result, we confirmed that the effective heat transfer state is obtained for developing a turbulent spot rather than a fully developed state. It attains the maximum when the turbulent spot grows the half size of the computational domain. Moreover, much effective heat transfer state was obtained for developing in streamwise direction rather than in spanwise direction.