Vortical Perturbations in Shear Flow, Scattered at a Hard Wall – Pressure Release Wall Transition
نویسندگان
چکیده
An analytically exact solution for the problem of low Mach number (i.e. incompressible) incident vorticity scattering at a hard to pressure release (Z = 0) wall transition is obtained using the Wiener-Hopf method. Harmonic vortical perturbations of inviscid linear shear flow are scattered at the wall transition, which results in a pressure-velocity field which is qualitatively different for low shear and high shear cases. The incompressible field produces an acoustic outer field, which can be determined for the low shear case, including a U4 0 relation for the radiated power. This behaviour for Z = 0 is very similar to the asymptotic behaviour of the previously found solution for finite impedance [1]. This correspondence confirms the validity of this last solution.
منابع مشابه
Turbulence mechanism in Klebanoff transition: a quantitative comparison of experiment and direct numerical simulation
The mechanism of turbulence development in periodic Klebanoff transition in a boundary layer has been studied experimentally and in a direct numerical simulation (DNS) with controlled disturbance excitation. In order to compare the results quantitatively, the flow parameters were matched in both methods, thus providing complementary data with which the origin of turbulence in the transition pro...
متن کاملPULSATILE MOTION OF BLOOD IN A CIRCULAR TUBE OF VARYING CROSS-SECTION WITH SLIP FLOW
Pulsatile motion of blood in a circular tube of varying cross-section has been developed by considering slip flow at the tube wall and the blood to be a non- Newtonian biviscous incompressible fluid. The tube wall is supposed to be permeable and the fluid exchange across the wall is accounted for by prescribing the normal velocity of the fluid at the tube wall. The tangential velocity of the fl...
متن کاملWall-based Actuation for Transition Delay and Drag Reduction
Subjecting a boundary layer to sudden or changing strain can have a profound effect on the flow. In turbulent boundary layers, oscillating the wall has been shown in previous studies as a viable mechanism to reduce drag. At lower Reynolds numbers, and in particular in the transition regime, the flow response is complex. On the one hand, the three dimensionality of the base state can lead to new...
متن کاملStudy of Pulsatile Non-Newtonian Blood Flow Through Abdominal Aorta and Renal Arteries Incorporating Fluid- Structure Interaction
Background: The interaction between the blood and the vessel wall is of great clinical interest in studying cardiovascular diseases, the major causes of death in developed countries.Objective: To understand the effects of incorporating fluid-structure interaction into the simulation of blood flow through an anatomically realistic model of abdominal aorta and renal arteries reconstructed from CT...
متن کاملTurbulent Drag Reduction by Spanwise Wall Oscillations
The objective of this paper is to examine the effectiveness of wall oscillation as a control scheme of drag reduction. Two flow configurations are considered: constant flow rate and constant mean pressure gradient. The Navier-Stokes equations are solved using Fourier-Chebyshev spectral methods and the oscillation in sinusoidal form is enforced on the walls through boundary conditions for the sp...
متن کامل