Introduction This discussion is a qualitative treatment of a topic that is usually treated rigorously and quantitatively in engineering textbooks. This discussion is intended for the general audience of nonspecialists and will attempt to convey the main ideas behind aerodynamics of spheres in a qualitative manner, with a minimum number of mathematical equations. As the Latin roots of the word i...

In order to detect intermittent firstand higher-order correlation between a pair of signals in both time and frequency, a wavelet-based coherence and bicoherence technique was developed. Due to the limited averaging in a time-frequency coherence estimate, spurious correlated pockets were detected due to statistical variance. The introduction of multiresolution, localized integration windows was...

This study evaluated fluctuations in the output signal of a densimeter, an in situ suspended-sediment measurement device based on a very sensitive differential pressure transducer. Although the densimeter produced accurate less than 10% error results in the laboratory for concentrations of 10–1,000 mg/L, there was a much larger fluctuation in the field test output signal. These fluctuations wer...

T h is p u b li ca ti on i s av ai la b le f re e of c h ar ge f ro m : h t t p s : / / d o i . o r g / 1 0 . 6 0 2 8 / N I S T . T N . 1 9 4 4 Statistical properties such as the spectral density and spatial coherence of boundary layer turbulence affect bluff body aerodynamics and structural responses. In this report, the opensource toolbox OpenFOAM is employed to perform LES simulations of bou...

In this work three branches of Immersed Boundary Methods (IBM) are described and validated for incompressible aerodynamics and fluid-structure interactions. These three approaches are: Cut Cell method, Vortex-Penalization method and Forcing method. Two first techniques are validated for external bluff-body flows and the last one is used for fluid-structure interactions. The paper confirms the a...

The aerodynamic plasma actuators have shown to be efficient flow control devices in various applications. In this study the results of flow control experiments utilizing single dielectric barrier discharge plasma actuators to control flow separation and unsteady vortex shedding from a circular cylinder in cross-flow are reported. This work is motivated by the need to reduce landing gear noise f...

Abstract The hotplate precipitation gauge operates by means of a thermodynamic principle. It is composed small disk with two thin aluminum heated plates on the upper and lower faces. Each plate has three concentric rings to prevent hydrometeors from sliding off in strong wind. As for more widely used tipping-bucket weighing gauges, measurements are affected wind-induced bias due bluff-body aero...