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An experimental investigation of transition point over a quasi-2D swept wing by using hot film
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 229, Issue 2 , February , 2015 , Pages 243-255 ; 09544100 (ISSN) ; Soltani, M. R ; Masdari, M ; Davari, A ; Sharif University of Technology
SAGE Publications Ltd
2015
Abstract
In this study, we performed experiments to investigate the effect of sweep angle on the transition location of laminar flow to turbulent flow. Three half wing models were used, each having a different sweep angle but with the same aspect ratio in various angles of attack. Two flat plates were used at the ends of the swept wing models to prevent the flow from rolling up over the wing. By simulating flow over infinity swept wing by eliminating tip vertices, the effect of sweep angle on flow transition phenomenon was investigated. The experiments included the study of transition flow via hot-film sensors, which were glued on the wing surface. We found that the small leading-edge radius and low...
Effect of leading-edge roughness on boundary layer transition of an oscillating airfoil
, Article Scientia Iranica ; Volume 20, Issue 3 , 2013 , Pages 508-515 ; 10263098 (ISSN) ; Soltani, M. R ; Sharif University of Technology
2013
Abstract
A series of experiments were conducted to study the effect of leading-edge roughness on the state of the boundary layer of a wind turbine blade section using multiple hot-film sensors. The experiments involved static and dynamic tests, where airfoil motion was of plunging type oscillation. The application of surface grit roughness simulates surface irregularities that occur on the wind turbine blades. The measurements showed that increasing the angle of attack results in movement of transition locations toward the leading edge. Surface roughness moved the transition point toward the leading edge and caused early trailing edge turbulent separation, which resulted in reducing the effectiveness...
Experimental study of the boundary layer over an airfoil in plunging motion
, Article Acta Mechanica Sinica/Lixue Xuebao ; Volume 28, Issue 2 , 2012 , Pages 372-384 ; 05677718 (ISSN) ; Soltani, M. R ; Sharif University of Technology
Abstract
This is an experimental study on the boundary layer over an airfoil under steady and unsteady conditions. It specifically deals with the effect of plunging oscillation on the laminar/turbulent characteristics of the boundary layer. The wind tunnel measurements involved surface-mounted hot-film sensors and boundary-layer rake. The experiments were conducted at Reynolds numbers of 0.42×10 6 to 0.84 × 10 6 and the reduced frequency was varied from 0.01 to 0.11. The results of the quasi-wall-shear stress as well as the boundary layer velocity profiles provided important information about the state of the boundary layer over the suction surface of the airfoil in both static and dynamic cases. For...