the effect of a combined system of the bed suction and jet injection as a pier-scour countermeasure on the turbulent flow field is studied in a laboratory flume using an acoustic doppler velocimeter (adv). the three components of the velocities in the vertical symmetry plane in the equilibrium scour hole in front and rear of the pier under 3-jet injections and bed suction rate qs/q0 = 2%located...

An interesting development towards a robust particle fractionator is presented. Typically acoustic fractionators rely on time of flight in a constant acoustic field to separate different populations[1,2]. Such a system requires all particles to be concentrated to an initial known point before entering the acoustic field. As the particle population enters the acoustic field, the particles will m...

The current study presents the results of the aerodynamic noise prediction of the flow field around a NACA 0012 airfoil at a chord-based Reynolds number of 100,000 and at 8.4 degree angle of attack. An incompressible Large Eddy Simulation (LES) turbulence model is applied to obtain the instantaneous turbulent flow field. The noise prediction is performed by the Ffowcs Williams and Hawkings (FW-...

Objectives. To present a quantitative comparison of thermal patterns produced by the piston-in-a-baffle approach with those generated by a physiotherapy ultrasonic device and to show the dependency among thermal patterns and acoustic intensity distributions. Methods. The finite element (FE) method was used to model an ideal acoustic field and the produced thermal pattern to be compared with the...

In (3) φ is an arbitrary test function and ρ the density of the fluid. In consequence, to calculate the acoustic field and thus, to solve the acoustic wave equation, the impedance Za on the surface Γ has to be known. Hence, a measurement technique to determine the acoustic impedance is of great importance, because a realistic sound field can only be calculated, if the real acoustic impedance at...