Receptivity of flat-plate boundary layer in a non-uniform free stream (vorticity normal to the plate) Download PDF EPUB FB2
With boundary layer over flat plate with nose of various shape was investigated. The non-uniform flow was produced by laminar wake behind the wire placed normal to the plate upstream of the leading edge. Receptivity of Flat-Plate Boundary Layer in a Non-Uniform Free Stream (Vorticity Normal to the Plate) Final Report M.
Kogan, V. Shumilkin, M. Ustinov, and S. Zhigulev Central Aerohydrodynamics Institute (TsAGI), Zhukovski, Moscow Region, Russia National Aeronautics and Space Administration Langley Research Center Hampton, Virginia Receptivity of Flat-Plate Boundary Layer in a Non-Uniform Free Stream (Vorticity Normal to the Plate) Work is devoted to study of free-stream vorticity normal to leading edge interaction with boundary layer over plate and resulting flow distortion influence on laminar-turbulent transition.
In experiments made the wake behind the vertically Author: M. Kogan and M. Ustinov. A localized disturbance was introduced into the free stream from a small pipe located upstream of the leading edge of a flat plate.
The disturbance penetrated the boundary layer, and a so called boundary layer ‘puff’ was created, consisting of three longitudinal streaks with the maximum perturbation amplitude approximately in the middle of the boundary by: 7.
The non-uniform flow was produced by laminar or turbulent wakes behind a wire placed normal to the plate upstream of the leading edge. The theoretical part of the work is devoted to studying the unstable disturbance evolution in a boundary layer with strongly non-uniform velocity profiles similar to that produced by outer-flow : M.
Kogan. The receptivity of a flat plate boundary layer to a freestream axial vortex is discussed by Boiko . Zhong  investigated the leading-edge receptivity to freestream disturbance waves for.
The results show that the receptivity of the flat-plate boundary layer to free-stream fast acoustic waves leads to the excitation of both Mack modes and a family of stable modes, i.e.
mode I, mode II, etc. It is found that the forcing fast acoustic waves do not interact directly with the unstable Mack by: The receptivity of the boundary layer on a straight-wing model to controlled free stream disturbances is studied.
The disturbances are generated by a special source located upstream of the leading edge of the model. The measurements show that perturbations with a streamwise-extended structure arise in the boundary by: 2. The receptivity of hypersonic boundary layers to free-stream disturbances, which is the process of environmental disturbances initially entering the boundary layers and generating disturbance waves, is altered considerably by the presence.
Receptivity of supersonic boundary layer to acoustic disturbances interacting with a blunt leading edge of a flat plate is studied using a combined asymptotic and numerical approach. Get this from a library. Receptivity of flat-plate boundary layer in a non-uniform free stream (vorticity normal to the plate): final report.
[M N Kogan; Langley Research Center.;]. Receptivity of flat-plate boundary layer in a non-uniform free stream (vorticity normal to the plate): final report of TsAGI under cooperative agreement # NCCW a subsonic boundary layer to a free stream acoustic perturbation.
The heights of the roughnesses involved in the receptivity study are usually assumed to have a size much smaller than the boundary layer thickness in order to cause only a small distortion.
Receptivity of Flat-Plate Boundary Layer in a Non-Uniform Free Stream (Vorticity Normal to the Plate) by National Aeronautics and Space Administration NASA Kindle. presence of two dimensional surface inhomogeneity is. investigated numerically. It is shown that, an efficient. conversion of the acoustics input to an unstable.
eigenmode of the boundary layer depends strongly not. only on the shape but also on the width of surface. roughness trough the band of Fourier Components. In Fig. 28, the effective total drag of a flat plate, with suction from the leading edge at the rate calculated by Ulrich for complete stability, is plotted against Reynolds number, together with the normal turbulent drag and the theoretical laminar drag without Size: 1MB.
The response of the boundary layer on a flat plate with blunt nose to infinitesimally small non-uniformity in the freestream velocity along the span h Cited by: 4. The boundary‐layer receptivity resulting from acoustic forcing over a flat plate with a localized surface irregularity is analyzed using perturbation methods.
The length‐scale reduction, essential to acoustic receptivity, is captured within the framework of the classical stability by: Boundary layer receptivity of 2D laminar incompressible flow over a compliant surface is investigated numerically.
Free stream acoustic waves, propagating parallel to a flat plate with a compliant surface is : Qun Wan. The receptivity of a laminar boundary layer to free stream disturbances has been experimentally investigated through the introduction of deterministic localized disturbances upstream of a flat plate mounted in a wind by: On thermal boundary layers on a flat plate subjected to a variable heat flux boundary-layer on a flat plate by considering the case when a The analogous problem of free convection boundary-layer flow on a vertical plate immersed in a viscous (Newtonian) fluid with the prescribed wall heat flux given by (1) was discussed by MerkinCited by: Poster Session I.- Evaluation of Adjoint Based Methods for the Prediction of Receptivity.- Receptivity to Freestream Turbulence and the Effect of Longitudinal Vortices in Boundary Layer Transition.- Receptivity for a Flat Plate with a Rounded Leading-Edge.- Experiments on the Receptivity of a Boundary Layer to a Localized Free Stream Disturbance Boundary layer thickness.
The boundary layer thickness, δ, is the distance across a boundary layer from the walls to a point where the flow velocity has essentially reached the 'free stream' velocity. This distance is defined normal to the wall.
As the flow travels along the flat plate a boundary layer forms. Near the leading edge of the plate, which refers to the first point of flow contact, the flow will always be laminar. The boundary layer is very thin, and the fluid particles move in parallel planes which do not interact with each other (Anderson, ).
Since the boundary layer is believed to be convectively unstable, the receptivity phenomena are best illustrated by considering a small amplitude harmonic distortion with angular frequency ω ∗ superimposed on a subsonic or moderately low Mach number supersonic flow of an ideal gas past an infinitely thin flat plate with uniform free-stream Author: Marvin E.
Goldstein, Pierre Ricco. The properties of the boundary-layer over a at plate have been investigated analytically, experi-mentally and numerically employing XFOIL. With the theory from Blasius and von K arm an, the boundary-layer properties over an in nitesimally thin at plate have been investigated analytically.
A nite thickness plate, designed to behave. Receptivity for a Flat Plate with a Rounded Leading-Edge.- Experiments on the Receptivity of a Boundary Layer to a Localized Free Stream Disturbance.- Experimental Study of Flat-Plate Boundary Layer Receptivity to Vorticity Normal to Leading Edge.- Boundary Layer Longitudinal Localized Structures Control by Means of Spanwise Wall Oscillations.-Price: $ () Receptivity of a laminar boundary layer to the interaction of a three-dimensional roughness element with time-harmonic free-stream disturbances.
Journal of Fluid Mechanics 1, () The small time behaviour for the impulsively started flow Cited by: Experiments are described in which well-defined weak Free Stream Nonuniformity (FSN) is introduced by placing fine wires upstream of the leading edge of a flat plate.
Large amplitude spanwise thickness variations form in the boundary layer as a result of the interaction between the steady laminar wakes from the wires and the leading by: 7.
conditions (e.g. roughness), and boundary-layer response • Receptivity has many different paths through which to introduce disturbances into boundary layer. Among these, interaction of freestream sound or vorticity with – leading-edge curvature – discontinuities in surface curvature – surface inhomogeneities, –.
The method allows computation of normal mode amplitudes of the discrete and continuous spectra. Considered examples of boundary layers over a flat plate include periodic-in-time blowing and suction through the wall at free-stream Mach numbers M = 2 andand an array of roughness elements at M = and by: Experimental Studies of the Boundary Layer on a The flat plate that was used for these tests (Fig.
1) has been described in detail by Hastings and Sawyer 2. It was about m (35 in) wide and about m (65 in) long, and was provided with holes into which plain or boundary layer than in the free stream. The influence of these File Size: 7MB.boundary-layer thickness laminar transitional turbulent U(y) Tollmien-Schlichting resonance, waves fundamental / subharmonic vortices for small initial disturbances: U turbulence log c f - log Re x Standard scenario (A) for a 2-d flat-plate boundary layer .