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Showing 1 to 18 of 18 for “"vortex sheet"”.
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A simplified vortex sheet roll-up method for formation flight
… parameter as well as a truncation of the vortex sheet in the highly rolled-up areas are introduced in order to stabilize the computations. The trailing wing is simply modeled as a lifting line, and its induced drag is computed thanks to a near-field analysis. The results are compared to …
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Helicopter rotor blade loading calculations using an axisymmetric vortex sheet and the free wake method
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1988.
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I. Regular and chaotic motions in a wave tank, II, interactions between a free surface and a shed vortex sheet
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1992.
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Unsteady Flow and Force Development in the case of a Circular Cylinder
… that whilst the potential flow `added mass' vortex sheet distribution around a stationary object immersed in an accelerating freestream is correct in shape, it ascribes the vortex sheet to the wrong origin. Instead, the vortex sheet is found to develop as a result of external vorticity that …
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Finite-Wavelength Scattering of Incident Vorticity and Acoustic Waves at a Shrouded -Jet Exit
… As the vortical disturbances supported by a vortex-sheet model of the jet pass the sharp edge of the shroud exit some of the energy is scattered into acoustic waves. We quantify scattering into radiating acoustic modes by obtaining the far-field directivities. Of greater interest in the …
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Preliminary experiment and analysis of supersonic inlet buzz
… entrance blocking effect, as introduced by the vortex sheet theory. The sustained oscillatory cycle of the resulting solution suggested a possible explanation of the phenomenon by combination of the vortex sheet theory concept and the resonance analysis.
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A vortex-lattice method for Delta wing aerodynamics
… The lifting surface is modelled as a bound vortex sheet, while the wake is modelled as a force-free vortex sheet. The solution is obtained by the use of a unsteady Vortex-Lattice Method which includes the effect of leading edge separation. Numerical predictions for the aerodynamic loads and …
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Fully nonlinear interfacial waves in a bounded two-fluid system
… numerical studies of unbounded three-dimensional vortex sheets (see Introduction for a discussion and references). In the final part of this work we consider the vortex-sheet formulation of the exact nonlinear two-dimensional flow of a vortex sheet which is bounded in a channel. We derive a …
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Observations of misovortices within the 7 January 2014 Long Lake-Axis-Parallel lake-effect snow band during the Ontario Winter Lake-effect Systems Project
… instability (HSI) was the main mechanism for misovortexgenesis in two LLAP bands analyzed during the LLAP Project. With data from only a single mobile Doppler radar available, however, this hypothesis was not testable. In the present study, three-dimensional dual-Doppler (DD) wind syntheses reveal …
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Application of panel methods for subsonic aerodynamics
… flows. The lifting surface is modelled with a vortex sheet and the wakes by discrete vortices. As an imitation of the conditions at the trailing edge, stagnation conditions on both surfaces are used. The over-determined system is solved by an optimization scheme. The present predictions are in …
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Viscous flow past plates
… plate induced by and entrained into the leading vortex. A secondary entrainment of positive vorticity into the region of negative vorticity is also found. The maximum velocity decays as $t^{-1/4}$ over a large initial time interval. For the uniformly accelerated, we show evolution in the …
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Concurrent Aerodynamic Shape / Cost Design Of Magnetic Levitation Vehicles Using Multidisciplinary Design Optimization Techniques
… bluff bodies. The model employs a continuous vortex sheet to model the solid surface, discrete vortices to model the shed wake, the Stratford Criterion to determine the location of the turbulent separation, and the vorticity conservation condition to determine the strength of the shed …
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Numerical Investigation of the Wake of a Rectangular Wing
Wakes of lifting bodies contain vortex sheets that roll up into strong streamwise vortices. The long time behavior of such vortices depends on the turbulence in the wake and the stability characteristics of the vortices themselves. In the near wake of a rectangular wing the flow field consists of a …
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Effects of Turbulence Modeling on RANS Simulations of Tip Vortices
… with aspect ratio, , and Reynolds number, . Tip-vortex velocity profiles, vortex core and wake turbulence levels, and Reynolds stresses are compared with wind tunnel measurements. Three turbulence models for RANS closure are tested: the Lumley, Reece, and Rodi full Reynolds stress transport model …
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Modified source-type flame model and vorticity generated by the flame and bluff bodies
… developed to simulate the wrinkled laminar flame sheet flapping in weakly turbulent premixed combustion. The wrinkled laminar flame sheet is represented by a discrete distribution of volume sources called source disks. These source disks are utilized to produce the acceleration of combustion …
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Application of a Helmholtz resonator excited by grazing flow for manipulation of a turbulent boundary layer.
… momentum balance equation and combination of the vortex sheet with discrete vortex models. A parametric study of the resonator showed that when the orifice length is increased the pressure fluctuations within the resonator are reduced, potentially due to the larger skin friction inside the …
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Controlling non-equilibrium dynamics in lattice gas models
… a vector flow diagram akin to an infinite flat vortex sheet. We have studied the finite-size scaling of the particle density fluctuations in both temperature regions, and observed that it is controlled by the respective temperature values. If the colder subsystem is maintained at the KLS …