How Large Spheres spin and move in Turbulent Flows
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چکیده
he aim of this dissertation is to gain a better understanding of the agrangian dynamics of solid large spheres in a complex turbulent environment hereforea novel measurement technique to optically track the –dimensional dynamics – positionand absolute orientation – of large spheres advected by a complex ow is developed lthough the spheres diameter is comparable to the integral length of the underlying owwe nd intermittency for both the translation and the rotation oreover rotation andtranslation couple in agreement with a lift force part from the fact that the accelerationstatistics are not gaussian and the exchange of energy between the particle and the carrierow falls into the mathematical theory of large deviations dditionally we nd that theparticle diameter has a surprisingly strong in uence on how a particle samples the owhe –tracking technique is then applied to an instrumented particle which embarksa –accelerometer and a radiotransmission system to constantly emit the felt agrangianacceleration as it is advected in the ow easuring the particles absolute orientation isa crucial step here to project the acceleration measured by the particle into the laboratoryreference frame and enables us to compare the forces obtained by the two independentmeasurements ased thereon methods for interpreting the acceleration signals of theinstrumented particle are developed and tested
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تاریخ انتشار 2012