EXPERIMENTAL INVESTIGATION OF BOUNDARY LAYER STATE ON THE MODEL OF INTEGRATED DESIGN HIGH-SPEED VEHICLE AND ITS IMPACT UPON THE CONVERGENT INTAKE STARTING

2018 ◽  
Vol 49 (6) ◽  
pp. 595-609
Author(s):  
Stanislav Sergeevich Alyoshin ◽  
Valerii Nikolaevich Golubkin ◽  
Anatoly Aleksandrovich Gubanov ◽  
Ivan Valerievich Nazhimov ◽  
Vadim Alekseevich Talyzin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
High Speed ◽  
Integrated Design ◽  
High Speed Vehicle

Experimental Investigation on Flow Field in a Rotating Channel With a New TR-PIV System

2018 ◽  
Author(s):  
Shengjun Zhou ◽  
Haiwang Li ◽  
Zhi Tao ◽  
Ruquan You ◽  
Haoyu Duan
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Laser Diode ◽  
High Speed ◽  
Flow Behavior ◽  
Particle Image Velocimetry System ◽  
Main Stream ◽  
High Speed Camera ◽  
Time Resolved ◽  
Rotating Channel

In the current study, the influence of different rotation conditions on the flow behavior is experimentally investigated by a new system which is designed for time-resolved PIV measurements of the smooth channels at rotation conditions. The Reynolds number equals 15000 and the rotation number ranges from 0 to 0.392 with an interval of 0.098. This new time-resolved Particle Image Velocimetry system consists of a 10 Watts continuous laser diode and a high-speed camera. The laser diode can provide a less than 1mm thickness sheet light. 6400 frames can be captured in one second by the high-speed camera. These two parts of the system are fixed on a rotating disk. In this case, the relative velocity of flows in the rotating smooth square channel can be measured directly to reduce the measurement error. This system makes high-speed camera close to the rotating channel, which allows a high resolution for the measurements of main stream. In addition, high accuracy and temporal resolution realize a detailed analysis of boundary layer characteristics in rotation conditions. Based on this system, experimental investigation has been undertaken. Results are presented of the evolution of velocity and boundary layer thickness at various rotation numbers and different circumferential positions.

An Experimental Investigation on the Characteristics of Turbulent Boundary Layer Flows Over a Dimpled Surface

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Wenwu Zhou ◽  
Yu Rao ◽  
Hui Hu
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Turbulent Boundary Layer ◽  
Flat Plate ◽  
Surface Pressure ◽  
High Speed ◽  
Boundary Layer Flows ◽  
Piv Measurement ◽  
Measurement Results ◽  
Flow Features

An experimental investigation was conducted to quantify the characteristics of the turbulent boundary layer flows over a dimpled surface in comparison to those over a conventional flat plate. In addition to measuring surface pressure distributions to determine the friction factors of the test plates and to map the surface pressure inside the dimple cavity, a high-resolution digital particle image velocimetry (PIV) system was used to achieve detailed flow field measurements to quantify the characteristics of the turbulent boundary layer flows over the test plates and the evolution of the unsteady vortex structures inside the dimple cavity at the middle of the dimpled test plate. It was found that the friction factor of the dimpled plate would be about 30–80% higher than that of the flat plate, depending on the Reynolds number of the test cases. In comparison with those over a conventional flat surface, the flow characteristics of the turbulent boundary layer flows over the dimpled surface were found to be much more complicated with much stronger near-wall Reynolds stress and higher turbulence kinetic energy (TKE) levels, especially in the region near the back rims of the dimples. Many interesting flow features over the dimple surface, such as the separation of oncoming boundary layer flow from the dimpled surface when passing over the dimple front rim, the formation and periodic shedding of unsteady Kelvin–Helmholtz vortices in the shear layer over the dimple, the impingement of the high-speed incoming flow onto the back rim of the dimple, and the subsequent generation of strong upwash flow in the boundary flow to promote the turbulent mixing over the dimpled surface, were revealed clearly and quantitatively from the PIV measurement results. The quantitative measurement results are believed to be the first of its nature, which depict a vivid picture about the unique flow features over dimpled surfaces and their correlations with the enhanced heat transfer performance reported in previous studies.

scholarly journals Boundary Layer Transition Assessment on a Slender High-Speed Vehicle

2017 ◽  
Author(s):  
Johan Steelant ◽  
Andrea Passaro ◽  
Victor Fernandez Villace ◽  
Anatoly Gubanov ◽  
Dmitry Ivanyushkin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
High Speed Vehicle

scholarly journals Experimental Investigation of the Boundary Layer Transition on a Laminar Airfoil Using Infrared Thermography

2018 ◽  
Vol 180 ◽  
pp. 02040
Author(s):  
Tomáš Jelínek
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Wind Tunnel ◽  
Infrared Thermography ◽  
High Speed ◽  
Turbulent Boundary Layers ◽  
Boundary Layer Transition ◽  
Wind Tunnel Testing ◽  
Layer Transition ◽  
Displacement Thickness

The transition in the boundary layer is investigated using infrared thermography (IRT). The study is carried out on a laminar airfoil in the transonic intermittent in-draft wind tunnel. The transition in the boundary layer is evocated using transition-generator strips of different thicknesses at two Mach numbers: 0.4 and 0.8. The tested transition-generators thickness to boundary layer displacement thickness ratio was from 0.42 to 1.25. The Reynolds number respect to the airfoil chord is: Re = 1.0 – 1.4·106. The six cases for different transition-generators thickness ratios were compared. The behaviours of laminar and turbulent boundary layers are discussed. The use of IRT has been proven to be an appropriate tool for detecting the transition of the boundary layer in high-speed wind tunnel testing.

EXPERIMENTAL INVESTIGATION OF BOUNDARY LAYER STATE ON THE SURFACE OF HIGH-SPEED TEST VEHICLE MODEL

2019 ◽  
Vol 50 (1) ◽  
pp. 39-52
Author(s):  
Stanislav Sergeevich Alyoshin ◽  
Valerii Nikolaevich Golubkin ◽  
Anatoliy Aleksandrovich Gubanov ◽  
Ivan Valerievich Nazhimov ◽  
Yurii Grigoryevich Shevalev ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
High Speed ◽  
Vehicle Model ◽  
Test Vehicle ◽  
Speed Test

scholarly journals An Experimental Investigation Into the Performance of a Flush Water-Jet Inlet

2007 ◽  
Vol 51 (01) ◽  
pp. 1-21 ◽  
Author(s):  
P. A. Brandner ◽  
G. J. Walker
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
High Speed ◽  
Boundary Layer Separation ◽  
Water Jet ◽  
Tunnel Wall ◽  
Cavitation Inception ◽  
Wall Boundary Layer ◽  
Cfd Models ◽  
Flow Features

An experimental investigation of the flow within a generic flush type water-jet inlet has been carried out to identify the principal flow features and provide a basis for development of computational fluid dynamics (CFD) models. Tests were performed in a cavitation tunnel with the model inlet fitted to the test section ceiling, and effects of thickening the ingested tunnel wall boundary layer were investigated. The model was fitted with a range of instrumentation to investigate the ramp pressure distribution and boundary layer development, lip incidence, and pump face flow properties. Observations of lip and duct cavitation inception and behavior were also made. The results showed the inlet performance to be generally improved with the ingestion of a thicker boundary layer. The thickened boundary layer significantly reduced ramp boundary layer separation and distortion of flow at the notional pump face. However, a greater range of lip incidence occurred with the thickened boundary layer with consequent greater likelihood of lip separation and cavitation occurrence. Ideal lip incidence and pump face flow uniformity occurred at flow parameters significantly different from those for ideal pump face pressure recovery. Large developed cavities on the inlet lip were observed for a range of conditions typical of conventional high-speed vessel operation.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

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