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The interaction of vortices induced by a pair of microjets in the turbulent boundary layer


Experimental and numerical study of active and passive flow control are notable and highly practical subjects in aircraft and missiles. Fluid jets are invaluable tools for this purpose. Accordingly, the present study delves into the effects of a pair of air microjets on turbulent flow over a plate. For this purpose, numerical model results were verified by experimental data of flow over a plate in the presence of a pair of air jets. Next, vortex formation, merging, and dissipation into the flow were studied at velocity ratio, VR = 4.0, by changing the spacing between the pair of jets and their orientations. The vortex position relative to the floor and other vortices, vortex intensity, flow velocity, Reynolds stresses in different directions, and pressure are discussed. The best vortex-merging results were found in a pair of co-directional jets (d/D = 10) condition. A pair of co-directional jets (d/D = 10) produced better results than opposite ones (d/D = 10—ccr). In the configuration with d/D = 10, the vortex intensity was nearly 80% higher than that of the single jet case. Further, the pair of jets pushed the post-jet pressure rise around 30 cm away.

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This project is supported by National Natural Science Foundation of China (Grant No. 51575279).

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Correspondence to Cheng Xu.

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Pour Razzaghi, M.J., Xu, C. & Emamverdian, A. The interaction of vortices induced by a pair of microjets in the turbulent boundary layer. J Vis 25, 449–465 (2022).

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  • Pair of micro-jets
  • Turbulent boundary layer
  • Vortex formation
  • Merging vorticities
  • Longitudinal vortex dissipation
  • Numerical solution