Abstract
The effects of periodic perturbations applied upstream of the fence by blowing/suction through a wall-slit are studied by LDA and PIV to establish velocity and turbulence fields, reattachment length and structures in the shear layer above the recirculation region. Perturbations, depending on frequency and amplitude, serve as an effective means of flow management, yielding a reduction of the downstream reattachment length as high as 56 %. This reduction is caused by the promotion of coherent vortical structures resulting from multiple vortex-pairing processes and is most effective for sub-harmonic exitation. Results are presented for one Reynolds number, Reh = 1300, both without perturbation and with 3 amplitudes of perturbation at two Strouhal numbers, Sth= 0.15 and 0.3. A correlation is proposed for the reduction in reattachment length.
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Larsen, P.S., Schmidt, J.J., Ullum, U. (1999). Experimental Study of Temporal and Spatial Structures in Fence-On-Wall Testcase. In: Sørensen, J.N., Hopfinger, E.J., Aubry, N. (eds) IUTAM Symposium on Simulation and Identification of Organized Structures in Flows. Fluid Mechanics and Its Applications, vol 52. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-4601-2_3
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DOI: https://doi.org/10.1007/978-94-011-4601-2_3
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