WP-2 Basic Investigation of Transition Effect

Abstract

An important goal of the TFAST project was to study the effect of the location of transition in relation to the shock wave on the separation size, shock structure and unsteadiness of the interaction area. Boundary layer tripping (by wire or roughness) and flow control devices (Vortex Generators and cold plasma) were used for boundary layer transition induction. As flow control devices were used here in the laminar boundary layer for the first time, their effectiveness in transition induction was an important outcome. It was intended to determine in what way the application of these techniques induces transition. These methods should have a significantly different effect on boundary layer receptivity, i.e. the transition location. Apart from an improved understanding of operation control methods, the main objective was to localize the transition as far downstream as possible while ensuring a turbulent character of interaction. The final objective, involving all the partners, was to build a physical model of transition control devices. Establishing of such model would

Response of the Shock Wave/Boundary Layer Interaction to Disturbances Induced by the Plasma Discharge

“…In addition to the two classical cases, namely, shock wave impingement on a boundary layer and flow over a compression ramp [31], an important test case for studying 2D SWBLI is the transonic buffet of an airfoil. Due to its significant practical relevance, this phenomenon has been extensively investigated in experiments [32] and has been shown to correspond to the nonlinear saturation of a global unstable mode by Crouch et al [33] and Sartor et al [34].…”

Numerical and experimental study of the effect of gas blowing/suction through a perforated surface on the boundary layer at a supersonic Mach number

“…Since such an essential difference was not revealed in subsonic studies, assume that the non-equilibrium state of the turbulent boundary layer is caused by the shear flow interaction with local shock waves/expansion waves generated by local jets arising near the perforated insert holes. The cycle of works [10,11] devoted to studying the shock wave boundarylayer interaction has shown that the agreement between the experimental data and RANS calculations is observed mainly in simple 2D cases. Attempts to regard 3D effects result in the growth of difference between the calculations and measurements.…”

Расчетно-Экспериментальное Исследование Влияния Вдува/Отсоса Газа Через Перфорированную Поверхность На Пограничный Слой При Сверхзвуковом Числе Маха

“…Поскольку для дозвуковых исследований столь существенной разницы не выявлено, можно предположить, что неравновесность турбулентного пограничного слоя возникает из-за взаимодействия сдвигового течения с локальными ударными волнами/волнами разрежения, генераторами которых выступают локальные струйные течения, возникающие около отверстий перфорированной вставки. Цикл исследований [10,11], посвященный изучению области взаимодействия ударной волны с пограничным слоем, показывает, что совпадение эксперимента с расчетом RANS в основном наблюдается только для простых двумерных случаев. Попытка учета трехмерных эффектов (например, течение в угловой конфигурации) приводит к увеличению разницы между экспериментом и расчетом.…”