Evaluation of miniature vortex generators for flow control in Falkner-Skan boundary layers

• Vortex generators with heights comparable to displacement thickness are an effective means of producing persistent mean-flow streaks in laminar boundary layers. Inducing streaky base flows can suppress growth of unsteady disturbances which would otherwise incite laminar-to-turbulent transition. Previous experimental and numerical works have demonstrated the versatility of these miniature vortex generators (MVGs) in zero pressure gradient boundary layers. In this work, mean-flow disturbances developing from MVGs in adverse and favorable pressure gradient boundary layers are measured systemically to assess the possibility of extending MVG-based flow control to these scenarios. Boundary-layer streak amplitudes are measured across a range of Falkner-Skan m values and an empirical scaling is found in congruence with existing results. The effect of streaks on transition in an adverse pressure gradient boundary layer is also tested and moderate increases to laminar flow extents are observed.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

Nyckelord

Aerospace engineering

Aviation

Boundary layer flow

Boundary layers

Flow control

Laminar flow

Pressure gradient

Turbulent flow

Vortex flow

Adverse pressure gradient

Boundary layer streaks

Displacement thickness

Empirical scaling

Favorable pressure gradients

Laminar to turbulent transitions

Unsteady disturbance

Zero-pressure-gradient boundary layers

Laminar boundary layer

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