The effect of cooling on supersonic boundary-layer stability

Abstract

For a number of applications it is important to know the location of the boundary-layer transition from laminar to turbulent. At present it is generally recognized that the onset of turbulence is directly connected with the loss of stability of the initial laminar flow. In the overwhelming majority of cases experimental data on the influence of various factors upon the transition location agree well with the calculated data concerning the influence of these factors on the boundary-layer stability, i.e. the theory of stability may be used successfully to predict various experimental dependencies.The boundary-layer stability and the transition are considerably affected by heat transfer from the surface of the streamlined body. But, in this case, experimental data on the transition do not always correspond to the results of the stability theory. In particular, experimental works concerning the effect of cooling of the model surface on the supersonic boundary layer transition yield contradictory results (see e.g. Gaponov & Maslov 1980; Morkovin 1969). Some of the contradictions were removed by Demetriades (1978) and Lysenko & Maslov (1981), but on the whole the problem cannot be considered solved, primarily owing to the fact that many theoretical results have not yet been experimentally confirmed.In the present paper the experimental study of development of small natural disturbances in the boundary layer of a cooled flat plate for Mach numbers M = 2, 3 and 4 is described. It confirms the main conclusions of the linear theory of hydrodynamic stability concerning the fact that surface cooling: (i) stabilizes the first-mode disturbances; (ii) destabilizes the second-mode disturbances; (iii) may lead to the region of unstable frequencies of the first mode being divided into two; (iv) does not affect the interaction of acoustic waves and the supersonic boundary layer.

Wall heat transfer effects on Klebanoff modes and Tollmien–Schlichting waves in a compressible boundary layer

“…As the TS waves we consider are of low frequency because they are induced by the Klebanoff modes through the triggering of the Lam-Rott modes, they are identified as compressible first modes, 5 for which wall cooling has been confirmed to be stabilizing, both numerically 35,[44][45][46][47] and experimentally. 48,49 In Fig. 14, the real part of ū as a function of the downstream distance represents the wave packet of the growing disturbance.…”

Direct numerical simulation of breakdown to turbulence in a Mach 6 boundary layer over a porous surface

“…The linear stability theory prediction that the second mode constitutes the primary instability for M ϱ Ͼ 4 was corroborated by experiments and DNS. 5,8 Clearly, the use of experiments and accurate numerical simulations is not limited to the assessment of the linear stability theory. A number of important discoveries on transition at high speeds came from temporal and spatial DNS studies as well as from experiments, see, for example, Masad and Nayfeh, 9 Ng and Erlebacher, 10 Chang and Malik, 11 Sandham et al, 12 Adams and Kleiser, 13 Pruett and Chang, 14 Chokani, 15 Boutin et al, 16 Maslov et al, 17 Graziosi and Brown, 18 Fedorov, 19 Forgoston and Tumin, 20 Ma and Zhong, 21,22 Ricco and Wu, 23 and Balakumar.…”

Влияние Температуры Носовой Части Конуса На Спектры Возмущений В Гиперзвуковом Пограничном Слое

“…Известно, что нагрев, равномерно распределенный по всей поверхности обтекаемой потоком газа модели, приводит при гиперзвуковых скорос-тях к дестабилизации первой моды возмущений и стабилизации второй. Охлаждение производит противоположный эффект [3].…”