Recent investigations of laminar flow control for swept-wing boundarylayer flows provide promising results with respect to crossflow-transition delay using a technique called pinpoint suction. Strong, localized suction through holes accurately positioned with respect to the crossflow-vortex position can directly weaken the growth of secondary instabilities that are responsible for the final lam...

Summertime low-level winds over the ocean adjacent to the California coast are typically from the north, roughly parallel to the coastline. Past Point Conception the flow often turns eastward, thereby generating cyclonic vorticity in the California Bight. Clouds are frequently present when the cyclonic motion is well developed and at such times the circulation is referred to as a Catalina eddy....

Horizontal convection in a rectangular enclosure driven by a linear temperature profile along the bottom boundary is investigated numerically using a high-resolution spectralelement discretization in space and a third-order time integration scheme for velocity and temperature fields. A Boussinesq approximation is employed to model buoyancy. The emphasis of this study is on the scaling of Nussel...

Direct numerical simulationhas been carried out for turbulent  owovera rectangular trailing edge at aReynolds number of 1 £ £ 103 (based on the freestream quantities and the trailing-edge thickness) and ratio of boundarylayer displacement thickness to trailing-edge thickness close to unity. Two types of  ow control were studied: base transpiration and secondary splitter plate. Simulation of b...

Matsumura, Shin. Master of Science in Aeronautics and Astronautics, Purdue University, December, 2003. Streamwise Vortex Instability and Hypersonic BoundaryLayer Transition on the Hyper-2000. Major Professor: Steven P. Schneider. Despite the closely coupled multidisciplinary design of hypersonic airbreathing vehicles, the boundary layer transition mechanisms that are important on the forebody a...

This paper extends previous large-eddy simulations of the convective boundary layer over a surface with a spatially varying sensible heat flux. The heat flux variations are sinusoidal and onedimensional. The wavelength is 1500 or 4500 m (corresponding to 1.3 and 3.8 times the boundarylayer depth. respectively) and the wind speed is 0. 1 or 2 m sI. In every case the heat flux variation drives a ...

A voice production model has been studied by considering essential aerodynamic and acoustic phenomena in human phonation. Acoustic voice sources are produced by the temporal change of volume flow passing through the glottis. A precise flow analysis is therefore performed based on the boundarylayer approximation and the viscous-inviscid interaction between the boundary layer and core flow. This ...

Realistic specifications of the roughness length and zero-plane displacement are crucial in the boundarylayer parametrisation that plays an important role in numerical mesoscale models (Abdella and Mcfarlane 1996). Martano (2000) proposed a method for estimating the surface roughness length (z0) and the displacement height (d) from single-level sonic anemometer data. This method reduces the pro...

Numerical methods are used to investigate the separated flow over a finite flat plate when the flow at large distances is given by the stream function $a = xy and the plate is situated on the x axis from 1 to 1. The range of nominal Reynolds number is 10-800. Reduced-mesh calculations are used for fine resolution of the flow field in the immediate vicinity of the separation point. Streamlines, ...

Reactive halogens are responsible for boundarylayer ozone depletion and mercury deposition in Polar Regions during springtime. To investigate the source of reactive halogens in the air arriving at Barrow, Alaska, we measured BrO, an indicator of reactive halogen chemistry, and correlated its abundance with airmass histories derived from meteorological back trajectories and remotely sensed sea i...