“Non-free” interaction of plane shock waves and the boundary layer in the neighborhood of the leading edge of a plate with slip

Conical flow breakdown in non-free shock-wave/boundary-layer interaction

“…Moreover, this approach is valid only in the case in which separation is local and has no effect on the bow shock. However, since the actual intensity of the internal shock impinging on the boundary layer is not important for determining the disturbed flow properties, usually qualitative, it is convenient, as in the case α 1 = 0 [1][2][3][4], to take the angle of attack α of the plate A as the parameter controlling the shock-layer flow variation.…”

“…In accordance with the terminology adopted in [1][2][3][4], in the "non-free" shock-wave/boundary-layer interaction regime the leading edge impedes the upstream propagation of the boundary layer separation line which would occur in "free" interaction. The interest in this phenomenon is due to the fact that boundary layer separation and the associated shock structures, which occur in the boundary layers on threedimensional bodies when internal shocks impinge on the body surface, may not only have a local effect on the disturbed flow but may also lead to qualitative variations [5][6][7].…”

“…In the experiments [1][2][3][4] conducted on a 90 • dihedral model, when a shock generated by one corner face was normally incident on the other face set at zero incidence and having a swept leading edge, it was found that both in the flow regimes in which the boundary layer separation line is located near the leading edge and in the regimes corresponding to non-free interaction the disturbed flow remains conical and does not break down before the incident shock coincides with the leading edge. This is supported by the data obtained using different experimental techniques.…”

“…In particular, the angle of inclination of the oblique shock above the separation zone measured from photographs indicates that the shock belongs to the weak family. Thus, in non-free interaction on a plate set at zero incidence the effective "fluid wedge" of the separation zone does not lead to detachment of the shock formed above the separation region and breakdown of the conical flow [1][2][3][4].…”

“…The results of the experimental studies [1][2][3][4] suggest that the conical flow breakdown occurring near different conical bodies when the separation line reaches the sharp leading edges under shock layer conditions is due to either the interaction of the separated flow with the shock attached to the edges or the non-free interaction realized under special conditions on the leading edge.…”