Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"vortex method"”.
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A numerical study of vortex method schemes for two-dimensional incompressible flows
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001.
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Aerodynamic modeling of a 2-dimensional airfoil with a covert-inspired deployable flap using a discrete vortex method
… on the development of a low-order discrete vortex model meant to predict the lift of an airfoil with a covert-inspired flap. Results show that the discrete vortex model is able to reproduce the experimental results for certain flap deflection angles.
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Use of the Discrete Vortex Method to Calculate Wind Loads over a Surface-Mounted Prism and a Bridge Cross-Section with Flaps
This thesis aims at presenting the Discrete Vortex Method (DVM) as a tool to determine the flow field and associated wind loads over structures. Two structures are considered: the first is a surface-mounted prism and is used to simulate wind loads over low-rise structures. The second is a bridge …
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Computational simulation of buoyancy-driven flows using vortex methods
A new vortex method for simulating two-dimensional buoyancy-driven flows is presented. This Lagrangian method utilizes a discrete representation of the known density field along with the vorticity transport equation and Boussinesq approximation to yield the baroclinically-generated vorticity field, …
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Viscous streaming in 3D and its applications
… relevant as a label-free and contactless method for such applications. In this thesis, we extend an existing 3D numerical flow–structure interaction (FSI) solver based on Remeshed Vortex Method (RVM) for the simulation and analysis of 3D streaming flows. We validate the accuracy and …
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Contributions Toward Understanding the Effects of Rotor and Airframe Configurations On Brownout Dust Clouds
… incompressible, time-accurate Lagrangian free-vortex method, coupled to a semi-empirical approximation for the boundary layer flow near the ground. A surface singularity method was employed to represent the aerodynamic influence of a fuselage. A rigorous coupling strategy for the free-vortex …
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A Hybrid Vortex Solution for Surge Margin Enhancement in Axial Compressors
<p>A new vortex solution to the Simple Radial Equilibrium Equation (SREE) is presented that incorporates endwall effects into the preliminary design stage of a single stage, low pressure compressor with a hub-to-tip ratio of 0.4 and non-axial inlet flow. This vortex solution is proposed to overcome …
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Optimum Spanloads Incorporating Wing Structural Considerations And Formation Flying
… each airplane. For single aircraft, a discrete vortex method which performs the calculations in the Trefftz plane has been used to calculate optimum spanloads for non-coplanar multi-surface configurations. The method includes constraints for lift coefficient, pitching moment coefficient and wing …
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Viscous streaming-enhanced inertial particle transport
… that numerical simulations based on the Remeshed Vortex Method (RVM) can accurately and efficiently capture viscous streaming dynamics. We test this algorithm on a wide variety of settings while simultaneously exhibiting the resultant streaming flow--structures, demonstrating both streaming's …
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Studies On The Behaviour Of Solid Particles In Turbulent Gas Flows
… of the pseudo-turbulence was based upon a vortex method in which the velocity fluctuations of the turbulent flow were simulated by arrays of randomly positioned vortices. The calculation of the motion of the spherical particles was based upon the forces acting upon a particle as a function …
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Determination of a Simplified High-Order Vortex Equation for Radial Equilibrium with CFD Verification
… current design techniques utilizing a hybrid vortex model. This hybrid vortex model combines the well-established simple radial equilibrium vortex models into a higher order equation that will establish the basis for a more flow-accurate model. In this paper, we will discuss the basis and …
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Numerical simulation and control of a fluid structure interaction for a plate in a transverse flow
… Here an approach is proposed where a CFD method is coupled with a controller to provide a qualitative flow model, and a tool for the development and the validation of the control scheme. A rotating rigid flat plate in transverse flow is considered. For the CFD, a discrete vortex method is …
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Vortex driven flame dynamics and combustion instability
… are acoustic wave-flame interactions, flame-vortex interactions, equivalence ratio fluctuations, flame-wall interactions and the unsteady stretch rate. To investigate the flame- vortex interaction mechanism, a parametric study is performed in single and double expansion dump combustors. 2-D …
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The effects of atmospheric turbulence on fuel consumption in extended formation flight
… 10 to 40 spans), has been recently proposed as a method for reducing the induced drag of commercial aircraft. However, induced drag savings are not necessarily directly indicative of fuel savings. In a realistic environment, atmospheric turbulence will continuously perturb the formation’s aircraft …
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Optimization of the Aerodynamics of Small-scale Flapping Aircraft in Hover
… air vehicles, researchers need new computational methods to design these aircrafts efficiently. </p><p>In this dissertation, I will present three different methods of optimization for flapping flight with an emphasis on hovering with each their advantages and drawbacks. The first method was …
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Computational fluid dynamic based optimisation of an industrial axial fan for rapid prototyping
… done without the general assumption of the free-vortex method, which is not a necessity for fan design and other velocity distributions may be used. For this purpose, an enhanced finite volume discretisation method was developed. A penalty function minimisation, by means of an unconstrained …
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Fluid-structure interaction investigation of a medium-sized heliostat
… fuels but also photovoltaic solar technologies. Vortex shedding and the resultant transient loadings on a medium sized heliostat are investigated in this paper. Reynolds-Averaged Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) of an operational heliostat is used as a validation case. The …
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Analysis of High Angle of Attack Maneuvers to Enhance Understanding of the Aerodynamics of Perching
… testing and using a computational 2D Discrete Vortex Method (DVM). Using the 2D DVM allows the ability to determine whether a low order, two dimensional code can accurately predict an actual 3D flowfield generated by highly unsteady motions. The pitching motions are studied experimentally using …
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Extracting energy from unsteady flows through vortex control
Vortex control is a new paradigm in fluid mechanics, with applications to propulsion and wake reduction. A heaving and pitching hydrofoil placed in a flow with an array of oncoming vortices can achieve a very high propulsive efficiency and reduced wake signature. The canonical example of flow with …
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A GENERALIZED CONSERVATION OF CIRCULATION MODEL IN VORTICITY DYNAMICS AND ITS APPLICATION TO VORTEX CALCULATION METHOD
In nature, vortices and vortex motions are the principal phenomena during fluid flow. Except for inviscid potential flow where vorticity is zero, the viscous effects of fluid on solid can be completely represented by vorticity and vortex motions in the fluid. In the present thesis, the generation …
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