A Combined Numerical and Experimental Investigation of Transition in a Laminar Separation Bubble
نویسندگان
چکیده
A laminar boundary layer separates in a region of adverse pressure gradient, undergoes transition, and finally the turbulent boundary layer reattaches, forming a laminar separation bubble (LSB). Laminar-turbulent transition within such a LSB is investigated by means of Laser-Doppler-Anemometry (LDA), Particle Image Velocimetry (mono PIV and stereoscopic PIV (SPIV)) and direct numerical simulation (DNS). A method is presented to measure the amplification of small unsteady disturbances by means of phase-locked PIV. The role of unsteady disturbances with and without controlled spanwise variation in the occurring mechanism of transition are examined in detail. Observations for the development of small disturbances are compared to predictions from linear stability theory.
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