Single-layer algebraic model of apparent turbulent viscosity and modified effective length method

It is proposed to use the Prandtl–Van Driest formula in the entire region of a two-dimensional laminar–turbulent boundary layer to study convective heat transfer and friction on high-temperature structural elements of high-energy devices. A modern modification of V.S. Avduevsky effective length method is formulated to solve these problems. Experimental data on convective heat transfer obtained at extremely high Reynolds numbers are analyzed, for which it was possible to establish the position of the transition region on the surface of the blunt part of the tested models. A new modification of the Prandtl–Van Driest formula is proposed that takes into account the dependence of the Karman constant on the position of the transition region on the blunt part of the model. In turn, the ideology of the classical effective length method is applied to calculate not laminar–turbulent heat transfer as a whole but only the component due to turbulent pulsations in the gas. Satisfactory quality of the description of the analyzed experimental data on the entire surface of the blunt model is obtained, which occurs when the proposed calculation methods are applied.