An experimental technique for investigation of the behavior of acoustic wave propagation through a turbulent medium is discussed. The present study utilizes the ultrasonic travel-time technique to diagnose a grid-generated turbulence. The statistics of the travel-time variations of ultrasonic wave propagation along a path are used to determine some metrics of the turbulence. Experimental data o...

The noise generated by the interaction of a turbulent inflow with the leading edge of a flat plate or an airfoil is a dominant sound source, for example in rotor-stator configurations of fans and air condition units. Aeroacoustic research of this noise source often includes performing wind tunnel experiments, where the required incident turbulence is generated by passive grids or meshes. In cer...

We present experimental observations of the turbulence field generated by a rectangular fractal grid. For engineering tests in wind tunnels, grid can be used to produce turbulent flows with high intensities and large integral length scales. Our results also add previous knowledge nonequilibrium dissipation scaling, which is observed decaying turbulence, even though homogeneity isotropy are not ...

Ultrasonic measurement techniques can be used to determine some characteristics of turbulent flows. In this work measurements of the difference in propagation times of ultrasonic waves along two paths are combined with the Kolmogorov (j )-power law to study characteristics of grid-generated turbulence. The paper focuses on ultrasonic measurements of turbulent flow using the travel-time techniqu...

A total of 21 planar fractal grids pertaining to three different fractal families have been used in two different wind tunnels to generate turbulence. The resulting turbulent flows have been studied using hot wire anemometry. Irrespective of fractal family, the fractal-generated turbulent flows and their homogeneity, isotropy, and decay properties are strongly dependent on the fractal dimension...