On the use of miniaturized delta wings tomodulate the Blasius boundary layer

• Main Author: Lozano, Francisco
• Format: Others
• Language: English
• Published: KTH, Mekanik 2017
• Subjects: Engineering and Technology; Teknik och teknologier
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214075

The present study represents an experimental proof-of-concept of the use offree stream vortices to modulate the Blasius boundary layer in the spanwisedirection. Miniaturized delta wings have been employed to generate pairs ofcounter rotating vortices that, through the lift-up mechanism, create velocitystreaks which modulate the boundary layer. This study has been dedicatedto the design and characterization of the experimental set up in the BL windtunnel of KTH Mechanics. A 3-component LDV system has been used tocharacterize the ow eld.By analyzing the ow eld, it has been assessed that a streaky strucutre isindeed generated inside the boundary layer though this methodology. Amongthe dierent parameters in uencing the streaks generated, the angle of attackof the delta wings has been varied. For angles of 9 and 12 streaks with higherintensities than those generated inside the boundary layer, documented in theliterature, have been generated. For an angle of 3, they have been successfullygenerated and embedded inside the boundary layer. Further development ofthis technique could lead to its use in passive ow control strategies aiming atdelaying boundary layer transition.