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1	Direct Variational Method of Analysis for Elliptic Paraboloidal Shells of Translation Sun, Chung-Li 06 1900 (has links) <p> The Rayleigh-Ritz method of Trial Function has been adopted to solve problems of translational shells under uniform external pressure. The basic energetical expressions have been written in terms of direct tensor notation. The stress-strain displacement relations are given in linear sense. Three different kinds of boundary conditions --- all four edges fixed, one pair of edges fixed and another pair of edges simply supported, and all four edges simply supported --- have been analysed. The stress and moment resultants at different points of the shell have been computed by means of IBM 7040, and are plotted into curves and figures to show their variations. The convergence of the displacement function uz is roughly verified. Certain comparison with other established results have been made. The results obtained by the present approach are satisfactory, at least from an engineering point of view.</p> / Thesis / Master of Engineering (MEngr)
2	Investigation of a Phased Array of Circular Microstrip Patch Elements Conformal to a Paraboloidal Surface Kumar, Sharath 04 December 2006 (has links) This thesis investigates the performance of a phased array of antenna elements conforming to a paraboloidal surface. We hypothesize that such a conformal phased array would have performance comparable to that of a correspondingly sized planar array. The performance of a paraboloidal array of antenna elements was simulated using an array program, and the resulting gains, side-lobe levels, and half-power beamwidths compared to those of a similarly sized planar array. Furthermore, we propose a beam-forming feed network for this paraboloidal phased array, and discuss the influence that coupling between the elements could have on the array performance. Lastly, we propose that such an array be used in conjunction with a parabolic reflector antenna to form a versatile hybrid antenna with several potential applications. / Master of Science conformal arrays circular microstrip patch arrays paraboloidal arrays
3	Numerical simulation of an inertial spheroidal particle in Stokes flow / Numerisk simulering av en trög sfäroidisk partikel i Stokesflöde Bagge, Joar January 2015 (has links) Particle suspensions occur in many situations in nature and industry. In this master’s thesis, the motion of a single rigid spheroidal particle immersed in Stokes flow is studied numerically using a boundary integral method and a new specialized quadrature method known as quadrature by expansion (QBX). This method allows the spheroid to be massless or inertial, and placed in any kind of underlying Stokesian flow. A parameter study of the QBX method is presented, together with validation cases for spheroids in linear shear flow and quadratic flow. The QBX method is able to compute the force and torque on the spheroid as well as the resulting rigid body motion with small errors in a short time, typically less than one second per time step on a regular desktop computer. Novel results are presented for the motion of an inertial spheroid in quadratic flow, where in contrast to linear shear flow the shear rate is not constant. It is found that particle inertia induces a translational drift towards regions in the fluid with higher shear rate. / Partikelsuspensioner förekommer i många sammanhang i naturen och industrin. I denna masteruppsats studeras rörelsen hos en enstaka stel sfäroidisk partikel i Stokesflöde numeriskt med hjälp av en randintegralmetod och en ny specialiserad kvadraturmetod som kallas quadrature by expansion (QBX). Metoden fungerar för masslösa eller tröga sfäroider, som kan placeras i ett godtyckligt underliggande Stokesflöde. En parameterstudie av QBX-metoden presenteras, tillsammans med valideringsfall för sfäroider i linjärt skjuvflöde och kvadratiskt flöde. QBX-metoden kan beräkna kraften och momentet på sfäroiden samt den resulterande stelkroppsrörelsen med små fel på kort tid, typiskt mindre än en sekund per tidssteg på en vanlig persondator. Nya resultat presenteras för rörelsen hos en trög sfäroid i kvadratiskt flöde, där skjuvningen till skillnad från linjärt skjuvflöde inte är konstant. Det visar sig att partikeltröghet medför en drift i sidled mot områden i fluiden med högre skjuvning. Fluid mechanics Stokes flow rigid body dynamics spheroidal particles inertia integral equations boundary integrals double layer potentials quadrature by expansion Jeffery orbits linear shear flow quadratic flow paraboloidal flow Strömningsmekanik Stokesflöde stelkroppsdynamik sfäroidiska partiklar tröghet integralekvationer randintegraler dubbellagerpotentialer quadrature by expansion Jeffery-banor linjärt skjuvflöde kvadratiskt flöde paraboloidiskt flöde Computational Mathematics Beräkningsmatematik

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