Three-dimensional flow diagnostics by holographic diffraction image velocimetry

1997 ◽  
Author(s):  
James S. Slepicka ◽  
Soyoung S. Cha
Keyword(s):  
Three Dimensional ◽  
Diffraction Image ◽  
Three Dimensional Flow ◽  
Flow Diagnostics ◽  
Dimensional Flow ◽  
Image Velocimetry

Three Dimensional Flow Around a Biomimetic Unbounded Flapping Cantilever

2013 ◽  
Author(s):  
Andrew Eastman ◽  
Mark Kimber
Keyword(s):  
Thermal Management ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Numerical Studies ◽  
Image Velocimetry ◽  
Two Dimensional Flow ◽  
Simple Extrapolation ◽  
Insight Into

Macro-sized cantilevers oscillating in a fluid have been employed in applications ranging from thermal management to propulsion and represent a realistic tradeoff between full biomimicry and ease of fabrication. Surprisingly, the flow field generated upstream and downstream of the cantilever remains poorly understood. In order to properly control the resulting flow, further experimental and numerical studies are needed. From a two dimensional perspective, comprehensive analysis has been done, primarily through employing a single, very wide cantilever. However, many applications necessitate the usage of oscillating cantilevers whose oscillating amplitude is comparable to their width. As the region of analysis moves closer to a corner, where two edges of the slender cantilever meet, the flow becomes extremely three dimensional, rendering the two dimensional analysis tools less useful. The following paper seeks to further understand the highly three dimensional nature of the flow in addition to providing further insight into optimized flow control. Two perpendicular flow planes are analyzed in order to gather the x, y and z directional flow velocities using standard Particle Image Velocimetry measurements. It is shown that under certain circumstances, the resulting flow is atypical of what one would expect from a simple extrapolation from previous two dimensional flow analyses.

Three-Dimensional Flow Through a Compressor Cascade With Circulation Control

2012 ◽  
Author(s):  
S. Fischer ◽  
L. Müller ◽  
H. Saathoff ◽  
D. Kožulović
Keyword(s):  
Measurement Techniques ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Circulation Control ◽  
Compressor Cascade ◽  
Three Dimensional Flow ◽  
Trailing Edge ◽  
Dimensional Flow ◽  
Image Velocimetry ◽  
Flow Through

A compressor cascade with active circulation control at the trailing edge of the blades is presented. The main objective of the current work is to investigate the influence of the active blowing on the three dimensional flow field. Furthermore the estimation of the blowing efficiency is of great interest and will be considered in detail. Navier-Stokes simulations have been conducted and compared to low-speed wind tunnel measurements. With the particular measurement techniques (five-hole-probe measurements and particle image velocimetry) significant three-dimensional flow details are accessible. Further details near the trailing edge are analysed by PIV-measurements at different spanwise positions. These measurements show a good jet quality over the blade span.

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