Dependence of heat transfer to a pulsating stagnation flow on pulse characteristics

A detailed boundary-layer model is implemented to ascertain the influence of pulse shape, frequency, and amplitude on instantaneous and time-averaged convective heat transfer in a planar stagnation region formed beneath an incident periodic, pulsating flow with temperature-dependent kinematic viscosity and thermal conductivity. Interactions between low-frequency/high-amplitude flow pulsations and the nonlinearities in the governing equations lead to reductions in time-averaged Nusselt numbers up to 16%. Predictions are in good agreement with experimental results. A means to suppress heat transfer is thus suggested that may have practical application to gas turbines where blades are exposed to a periodic flow. Phase portraits, Poincare maps, Fourier spectra, and Lyapunov exponents are used to elucidate the most complex solutions.