scholarly journals Investigation of Flow Field near and around a Darrieus Rotor by Flow Visualization and Image Analysis

1996 ◽  
Vol 16 (Supplement2) ◽  
pp. 167-170
Author(s):  
Nobuyuki FUJISAWA ◽  
Mitsuyoshi TAKEUCHI ◽  
Youichi HORI
Keyword(s):  
Image Analysis ◽  
Flow Field ◽  
Flow Visualization ◽  
Darrieus Rotor

scholarly journals Flow Visualization in Intersecting Ducts by Color Image Analysis

1996 ◽  
Vol 16 (1Supplement) ◽  
pp. 273-276
Author(s):  
Shinzaburo UMEDA ◽  
Wen-Jei YANG ◽  
Yoshiaki UETANI
Keyword(s):  
Image Analysis ◽  
Flow Visualization ◽  
Color Image ◽  
Color Image Analysis

The Role of Vortices and Unsteady Effects During the Hovering Flight of Dragonflies

1979 ◽  
Vol 83 (1) ◽  
pp. 59-77 ◽  
Author(s):  
STUART B. SAVAGE ◽  
BARRY G. NEWMAN ◽  
DENIS T.-M. WONG
Keyword(s):  
Steady State ◽  
Flow Field ◽  
Flow Visualization ◽  
Inviscid Flow ◽  
Physical Explanation ◽  
Hovering Flight ◽  
Wing Motion ◽  
Unsteady Effects ◽  
Animal Flight

Weis-Fogh and Norberg concluded that steady-state aerodynamics is incapable of explaining how the dragonfly supports its weight during hovering. Norberg also concluded that the wing kinematics of Aeschna juncea L., as determined photographically, are incompatible with those proposed by Weis-Fogh for his Flip mechanism. The present paper has proposed an alternative lift-generating mechanism, various aspects of which are novel from the standpoint of animal flight. Flow visualization tests performed in water established the flow field during a complete cycle of the idealized wing motion. Using this information and unsteady inviscid flow theory the forces were analysed. A plausible balance of horizontal forces and more than sufficient lift were obtained. A physical explanation of the theory is provided for those who do not wish to study the mathematical details.

scholarly journals Aerodynamics of Flapping Wing at Low Reynolds Numbers: Force Measurement and Flow Visualization

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Abhijit Banerjee ◽  
Saurav K. Ghosh ◽  
Debopam Das
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Flow Visualization ◽  
Force Measurement ◽  
Reynolds Numbers ◽  
Flapping Flight ◽  
Water Tank ◽  
Cross Sectional ◽  
Piv Measurement ◽  
The Difference

Flow field of a butterfly mimicking flapping model with plan form of various shapes and butterfly-shaped wings is studied. The nature of the unsteady flow and embedded vortical structures are obtained at chord cross-sectional plane of the scaled wings to understand the dynamics of insect flapping flight. Flow visualization and PIV experiments are carried out for the better understanding of the flow field. The model being studied has a single degree of freedom of flapping. The wing flexibility adds another degree to a certain extent introducing feathering effect in the kinematics. The mechanisms that produce high lift and considerable thrust during the flapping motion are identified. The effect of the Reynolds number on the flapping flight is studied by varying the wing size and the flapping frequency. Force measurements are carried out to study the variations of lift forces in the Reynolds number (Re) range of 3000 to 7000. Force experiments are conducted both at zero and finite forward velocity in a wind tunnel. Flow visualization as well as PIV measurement is conducted only at zero forward velocity in a stagnant water tank and in air, respectively. The aim here is to measure the aerodynamic lift force and visualize the flow field and notice the difference with different Reynolds number (Re), and flapping frequency (f), and advance ratios (J=U∞/2ϕfR).

Flow visualization/digital image analysis of saltating particle motions

1990 ◽  
Vol 9 (1-2) ◽  
pp. 65-73 ◽  
Author(s):  
A. D. Ciccone ◽  
J. G. Kawall ◽  
J. F. Keffer
Keyword(s):  
Image Analysis ◽  
Flow Visualization ◽  
Digital Image ◽  
Digital Image Analysis

A video image analysis system for concentration measurements and flow visualization in building wakes

1991 ◽  
Vol 25 (7) ◽  
pp. 1211-1225 ◽  
Author(s):  
J.T. Lee ◽  
Darrell L. Call ◽  
Robert E. Lawson ◽  
William E. Clements ◽  
Donald E. Hoard
Keyword(s):  
Image Analysis ◽  
Flow Visualization ◽  
Video Image ◽  
Image Analysis System ◽  
Video Image Analysis ◽  
Concentration Measurements ◽  
Analysis System

scholarly journals Flow visualization of low speed ventilation flow in a room and flow image analysis by using a density correlation method

1993 ◽  
Vol 13 (Supplement2) ◽  
pp. 29-34
Author(s):  
T. KOBAYASHI ◽  
T. SAGA ◽  
T. SEGAWA ◽  
Y. KOBAYASHI ◽  
T. WADA ◽  
...  
Keyword(s):  
Image Analysis ◽  
Flow Visualization ◽  
Correlation Method ◽  
Low Speed ◽  
Density Correlation ◽  
Flow Image

scholarly journals Effect of vortex generator on the flow field over a conventional delta wing in subsonic flow condition at higher angles of attack

2021 ◽  
Vol 49 (2) ◽  
pp. 395-400
Author(s):  
Manthan Patil ◽  
Rajesh Gawade ◽  
Shubham Potdar ◽  
Khushabu Nadaf ◽  
Sanoj Suresh ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Visualization ◽  
Drag Coefficient ◽  
Subsonic Flow ◽  
Delta Wing ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Vortex Generator ◽  
Oil Flow ◽  
Oil Flow Visualization

Flow over a conventional delta wing has been studied experimentally at a subsonic flow of 20 m/sec and the flow field developed at higher angle of attack varying from 10° to 20° has been captured. A vortex generator is mounted on the leeward surface of the delta wing and its effect on the flow field is studied. The set of wing tip vortices generated over the delta wing is captured by the oil flow visualization and the streamline over the delta wing surface captured with and without a vortex generator are compared. Based on the qualitative results, the effect of the vortex generator on the lift coefficient is anticipated. Further, force measurement is carried out to quantitatively analyze the effect of vortex generator on the lift and drag coefficient experienced by the delta wing and justify the anticipation made out of the qualitative oil flow visualization tests. In the present study, the effect of mounting of a vortex generator is found to be minimal on the lift coefficient experienced by the delta wing. However, a significant reduction in the drag coefficient with increase in angle of attack was observed by mounting a typical vortex generator.

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