Browsing by Author "Mathioulakis, Dimitri"
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- Steady and unsteady cascade measurementsMathioulakis, Dimitri (Virginia Polytechnic Institute and State University, 1982)Velocity and turbulence intensity measurements were made in a linear stationary cascade of compressor blades under high angles of attack. Laser-doppler velocimetry and flow visualization were used. A method was developed for inducing propagating stall and some triggered ensemble averaged velocity records were obtained. An inviscid model was developed in order to predict the separated flow over an isolated blade. The results of this model were qualitatively compared to the pictures obtained by flow visualization. Finally initial attempts were made for extension of this model to predict the unsteady flow in a cascade.
- Vorticity shedding over two-dimensional bodiesMathioulakis, Dimitri (Virginia Tech, 1985)The vorticity shedding characteristics in attached and separated regions were investigated over three configurations, namely a backward facing circular arc, an ellipse at an angle of attack and a pitching airfoil. A fully automated data acquisition system was developed, including a two-component Laser-Velocimetry system in backscatter mode, an accurately controlled traversing mechanism and a MINK-11 minicomputer. Two-component velocity measurements were obtained over the above mentioned bodies, with steady and unsteady free streams. Emphasis was concentrated on the separation region, the free-shear layers and the wake downstream of these bodies. Two inviscid vortex models were developed to predict two different flow phenomena, namely the separated flow over a circular cylinder started impulsively from rest and propagating stall over a linear stationary cascade.