| description abstract | A high-order finite-difference scheme is employed to discretize the complete Navier-Stokes equations in order to simulate the hypersonic unsteady flowfield over a blunt cone. The hypersonic unsteady flowfield due to large-amplitude entropy disturbance under different wall temperatures is calculated. Then, the effects of the wall temperature on the hypersonic flowfield and boundary layer response are discussed. A Fourier spectral analysis is used to investigate the generation and evolution characteristics of different boundary layer disturbance waves with different wall temperatures. Results show the following: (1) Under freestream entropy disturbance, the pressure disturbance waves generated in the boundary layer have frequency characteristics directly related to the freestream disturbance wave, which gradually weakens as the disturbance waves evolve along streamwise. (2) Wall temperatures can significantly affect the evolution of boundary layer disturbance waves, and the response of a boundary layer disturbance to wall temperature change in different regions presents different characteristics. (3) In the nose region, the influence of the wall temperature on different frequency disturbance waves is relatively small. As the disturbance wave develops downstream, the influence of the wall temperature on the amplitude of the different frequency disturbance waves in the boundary layer increases gradually, and this indicates that the influence of the wall temperature on the evolution of different frequencies in the boundary layer disturbance waves is cumulative. (4) Wall temperatures have different effects on boundary layer disturbance waves with different frequencies. The fundamental frequency mode waves in the boundary layer are relatively insensitive to the wall temperature, and wall temperatures have relatively greater effects on the harmonic frequencies above the second order, especially the second, third, and fourth order harmonic frequencies. In general, a higher wall temperature has an inhibitory effect on the attenuation of the fundamental mode components, and a cold wall has a significant positive effect on the advance growth or inhibition attenuation of the amplitudes of harmonic disturbances of all orders. | |
