Volf Ya. Borovoy

Bio: Volf Ya. Borovoy is an academic researcher. The author has contributed to research in topics: Mach number & Reynolds number. The author has an hindex of 5, co-authored 13 publications receiving 102 citations.

Pressure sensitive paint application in shock wind tunnel

Abstract: Pressure sensitive paint technology is a new optical pressure measurement method providing new opportunities for non-contact pressure measurements. Specific features of PSP-technology for shock wind tunnel are discussed. An optical pressure measurement system for instantaneous measurements is described. Results of pressure measurements on a cylinder at Mach 6 are presented.

Two-Dimensional Shock-Wave/Boundary-Layer Interaction in the Presence of Entropy Layer

Abstract: Results of experimental and numerical study of gas flow and heat transfer in the region of interference of the impinging oblique shock wave with the near-wall flow on sharp and blunt plates are presented. The study is performed for the freestream Mach numbers from 5 to 10 and Reynolds numbers from 0.3×106 to 27×106 corresponding to the laminar and turbulent undisturbed boundary layers. The plate bluntness, location of the impinging shock, and the shock strength are varied. It is shown that the plate bluntness significantly reduces the heat transfer in the interference region due to the increase of separation-zone size and the reduction of gas density in the high-entropy layer. As the plate bluntness increases the heat transfer decays to a certain threshold value of the bluntness radius. The bluntness effect on the heat transfer increases and the bluntness threshold value decreases with the freestream Mach number.

Temperature sensitive paint application for investigation of boundary layer transition in short-duration wind tunnels

Abstract: Application of Temperature Senstive Paint (TSP) technology for investigation of boundary layer transition in short-duration wind tunnels is presented. Investigations were made on sharp and blunted flat plates in UT-1 wind tunnel of TsAGI operated in Ludwieg scheme at Mach numbers 5, 6, and 8 (Reynolds numbers from 5.5 · 106 to 26 · 106 ). Both natural and induced boundary layer transitions were investigated.

Entropy-Layer Influence on Single-Fin and Double-Fin/Boundary-Layer Interactions

Abstract: The influence of the entropy layer generated by the blunted-plate leading edge on the flow over a single fin or pair of fins installed on the plate is studied experimentally and numerically. Experiments are carried out in a Ludwieg-type wind tunnel at Mach numbers of M∞=5, 6, and 8 and Reynolds numbers from 7×106 to 27×106 at turbulent, transitional, and laminar boundary layers on the plate in front of the fins. Panoramic optical methods are used for measurements of heat flux and pressure. Flow visualization is done as well. It is shown that even a small blunting of the plate leading edge considerably changes the heat transfer, pressure, and shear-stress distributions at the shock wave/boundary-layer interactions; and, under certain conditions, it causes changes of the flow structure.

A review of pressure-sensitive paint for high-speed and unsteady aerodynamics

Abstract: The current paper describes the development of pressure-sensitive paint (PSP) technology as an advanced measurement technique for unsteady flow fields and short-duration wind tunnels. Newly developed paint formulations have step response times approaching 1 μs, making them suitable for a wide range of unsteady testing. Developments in binder technology are discussed, which have resulted in new binder formulations such as anodized aluminium, thin-layer chromatography plate, polymer/ceramic, and poly(TMSP) PSP. The current paper also details modeling work done to describe the gas diffusion properties within the paint binder and understand the limitations of the paint response characteristics. Various dynamic calibration techniques for PSP are discussed, along with summaries of typical response times. A review of unsteady and high-speed PSP applications is presented, including experiments with shock tubes, hypersonic tunnels, unsteady delta wing aerodynamics, fluidic oscillator flows, Hartmann tube o...

Heat-Transfer Measurements in Hypersonic Flow Using Luminescent Coating Techniques

Abstract: Thedevelopmentandapplicationofhigh-speedimagingandluminescentcoatingtechniquestomeasurefull-e eld surface heat-transfer rates in short-duration hypersonic e ow is presented. Tests were performed on an indented cone model at the 48-in. shock tunnel and the LENS I tunnel facilities at Calspan— University of Buffalo Research Center. Nominal test conditions ranged between Mach numbers of 9.5 and 11.1 and Reynolds numbers of 1:4 £ 10 5 and 3 £ 10 5 m ii 1 with run times of less than 10 ms. Processed submillisecond images show the threedimensional, time-dependent development of the embedded separated e ow and shock/boundary-layer interaction into a steady axisymmetric structure bounded by regions of laminar e ow. Conversion from processed image data to full-e eld heat-transfer measurements were performed using both an in situ calibration with thin-e lm platinum heat-transfer gauges as well as an a priori temperature calibration and transient heat-transfer theory. In situ calibrations displayed excellent correlation with surface-mounted gauges, whereas a priori calibrations showed a larger susceptibility to bias errors.

Temperature- and Pressure-Sensitive Paint Measurements in Short-Duration Hypersonic Flow

Abstract: Surface temperatures and pressures were measured on an elliptic cone lifting body in a hypersonic e owe eld using thin-e lm (» 5πm) temperature- and pressure-sensitive paints (TSPs and PSPs ). The tests were conducted in the 48-inch hypersonic shock tunnel (48-inch HST) at Calspan‐University of Buffalo Research Center and were part of a more comprehensive experimental study examining the three-dimensional characteristics of laminar, transitional, and turbulent e ow over the model. Measurement opportunity in the 48-inch HST was limited by the short duration of steady freestream conditions of the driven gas; image acquisition times were » 3 ms. Images of the coatings applied to the broad side of the symmetric elliptic cone were calibrated with in situ static pressure and surface-e lm temperature measurements. The TSP results illustrate the higher heat transfer rates and change in boundary-layer transition over the model surface caused by the nose geometry, and the PSP results show a mild pressure gradient over the interrogated surface region. Submillisecond TSP acquisition using a high-speed imager demonstrated the feasibility of measuring the surface temperature rise.