This work addresses the simulation of transitional flow over airfoils under low Reynolds number conditions (Rec ≤ 60000). The flow solutions are obtained by means of an Implicit Large Eddy Simulation (ILES) using a newly developed unstructured, parallel solver that employs the high-order spectral difference (SD) method for spatial discretization. The calculations are performed on the SD7003 air...

In this paper we study piecewise linear differential systems formed by two regions separated by a straight line so that each system has a real saddle point in its region of definition. If both saddles are conveniently situated, they produce a transition flow from a segment of the splitting line to another segment of the same line, and this produces a generalized singular point on the line. This...

Flow characteristics of water were tested in a rectangular microchannel for Reynolds number (Re) between 0 and 446 by terahertz time domain spectroscopy (THz-TDS). Output THz peak trough intensities and the calculated absorbances of the flow were analyzed theoretically. The results show a rapid change for Re < 250 and a slow change as Re increases, which is caused by the early transition from l...

Discrete roughness boundary layer transition results on a Shuttle Orbiter model in the NASA Langley Research Center 20-Inch Mach 6 Air Tunnel have been reanalyzed with new boundary layer calculations to provide consistency for comparison to other published results. The experimental results were previously obtained utilizing the phosphor thermography system to monitor the status of the boundary ...

An easy-to-interpret kinematic quantity measuring the average corotation of material line segments near a point is introduced and applied to vortex identification. At a given point, the vector of average corotation of line segments is defined as the average of the instantaneous local rigid-body rotation over ‘all planar cross-sections’ passing through the examined point. The vortex identificati...

(2005) Mixed layer depth determination in the Barcelona costal area from regular lidar measurements: methods, results and limitations. Boundary-Layer Meteorology (in press) ABSTRACT Regular aerosol backscatter measurements using an elastic-backscatter lidar were performed understand the physical and chemical processes taking place in the low troposphere, was one of the major parameters to be re...

We present stability analyses for the boundary-layer flow over broad cones (half-angle ψ > 40◦) rotating in imposed axial flows. Preliminary convective instability analyses are presented that are based on the Orr–Sommerfeld equation for a variety of axial-flow speeds. The results are discussed in terms of the limited existing experimental data and previous stability analyses on related bodies. ...

The effect of inlet conditions on the mixing of a passive scalar was investigated in a planar shear layer with inlet boundary layers that were laminar, tripped and naturally turbulent–transitional. Planar laser-induced fluorescence measurements of acetone were used to directly evaluate the shear layer structure, and were processed to determine probability density functions ~PDFs! of the mixture...

To evaluate the effect of turbulent heating in the thermal balance of interstellar clouds, we develop an extension of the log-Poisson intermittency model to supersonic turbulence. The model depends on a parameter, d, interpreted as the dimension of the most dissipative structures. By comparing the model with the probability distribution of the turbulent dissipation rate in a simulation of super...

We have calculated the radial non-adiabatic p-mode oscillations of the solar models. Based on a statistical theory of non-local convection, both the thermodynamic and kinetic couplings between convection and oscillations are finely treated. The turbulent pressure, turbulent viscosity, turbulent thermal flux and turbulent kinetic flux are all self-consistently included in the equations. The depa...