Measurement of unsteady boundary layer developed on an oscillating airfoil using multiple hot-film sensors

1998 ◽  
Vol 25 (2) ◽  
pp. 108-117 ◽  
Author(s):  
T. Lee ◽  
S. Basu
Keyword(s):  
Boundary Layer ◽  
Unsteady Boundary Layer ◽  
Oscillating Airfoil ◽  
Hot Film

High sensitive flexible hot-film sensor for measurement of unsteady boundary layer flow

2020 ◽  
Vol 29 (3) ◽  
pp. 035023
Author(s):  
Baoyun Sun ◽  
Binghe Ma ◽  
Pengbin Wang ◽  
Jian Luo ◽  
Jinjun Deng ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Unsteady Boundary Layer ◽  
Film Sensor ◽  
Layer Flow ◽  
Hot Film ◽  
Hot Film Sensor

scholarly journals An Experiment on Unsteady Flow Over an Oscillating Airfoil

1991 ◽  
Author(s):  
L. He ◽  
J. D. Denton
Keyword(s):  
Boundary Layer ◽  
Unsteady Flow ◽  
Wave Pattern ◽  
Loading Conditions ◽  
Unsteady Boundary Layer ◽  
Suction Surface ◽  
Pressure Transducers ◽  
Reduced Frequency ◽  
Unsteady Viscous Flow ◽  
Hot Film

In order to enhance understanding of viscous-dominated blade flutter and to provide experimental data for validating unsteady viscous flow solutions, unsteady flow over a 2-D NACA-65 airfoil oscillating in torsion at an amplitude of 2° and a reduced frequency up to 0.69 has been experimentally investigated in a low-speed wind tunnel under different loading conditions. Unsteady pressure distribution is measured on both suction and pressure surfaces using pressure transducers. On the suction surface hot-film measurements are conducted to indicate the development of the unsteady boundary layer. Unsteady boundary layer behaviour and its effects on the airfoil’s aeroelasticity at the different loading conditions are demonstrated. The results also throw some light on understanding the onset mechanism of “dynamic stall” which involves a persistent convective pressure wave pattern with marked unstable aeroelastic characteristics.

Effect of Reduced Frequency on the Boundary Layer of a Plunging Airfoil

2010 ◽  
Author(s):  
F. Rasi Marzabadi ◽  
M. R. Soltani ◽  
M. Masdari
Keyword(s):  
Boundary Layer ◽  
Separation Bubble ◽  
Reynolds Numbers ◽  
Boundary Layer Transition ◽  
Unsteady Boundary Layer ◽  
Layer Transition ◽  
Laminar Separation ◽  
Pressure Transducers ◽  
Reduced Frequency ◽  
Hot Film

This investigation addresses the boundary layer study of a plunging airfoil. It specifically concerns the effect of reduced frequency on transition and separation/reattachment of the unsteady boundary layer. The wind tunnel measurements were conducted using multiple hot-film sensors, pressure transducers and a boundary-layer rake, at Reynolds numbers of 0.42 to 0.84 million, and over reduced frequencies from 0.05 to 0.11. It was observed the boundary layer transition occurs by a laminar separation bubble. The unsteady laminar separation is promoted (delayed) by the increase of the reduced frequency in upstroke (downstroke) portion of the equivalent angle of attack.

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