Search for dissertations about: "linearized unsteady numerical method"
Showing result 1 - 5 of 6 swedish dissertations containing the words linearized unsteady numerical method.
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1. A Linearized Euler Method for Unsteady Flow in Axial-Flow Turbomachines
Abstract : A linear Euler method for analysing unsteady inviscid compressible quasi three- dimensional flows in oscillating cascades is developed. It is applicable to both blade flutter and forced response problems. READ MORE
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2. Experimental Investigation of Three-Dimensional Mechanisms in Low-Pressure Turbine Flutter
Abstract : The continuous trend in gas turbine design towards lighter, more powerful and more reliable engines on one side and use of alternative fuels on the other side renders flutter problems as one of the paramount challenges in engine design. Flutter denotes a self-excited and self-sustained aeroelastic instability phenomenon that can lead to material fatigue and eventually damage of structure in a short period of time unless properly damped. READ MORE
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3. Analysis and control of transitional shear flows using global modes
Abstract : In this thesis direct numerical simulations are used to investigate two phenomenain shear flows: laminar-turbulent transition over a flat plate and periodicvortex shedding induced by a jet in cross flow. The emphasis is on understanding and controlling the flow dynamics using tools from dynamical systems and control theory. READ MORE
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4. Thermo-Acoustic Properties in Combustion Chambers
Abstract : Design and analysis methods for gas turbine combustors or afterburners have to be improved in particular regarding the prediction of combustion instabilites. A methodology, which combines the use of a linearized flow solver and an Arnoldi algorithm performing the eigenmode extraction procedure, resolves eigenmodes which are candidates to these instabilities. READ MORE
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5. Flutter in sectored turbine vanes
Abstract : In order to eliminate or reduce vibration problems inturbomachines without a high increase in the complexity of thevibratory behavior, the adjacent airfoils around the wheel areoften mechanically connected together with lacing wires, tip orpart-span shrouds in a number of identical sectors. Although anaerodynamic stabilizing effect of tying airfoils together ingroups on the whole cascade is indicated by numerical andexperimental studies, for some operating conditions suchsectored vane cascade can still remain unstable. READ MORE