Use of a Plasma Arc to Produce Large Surface Pressure Changes On a Flat Plate in a Mach 5 Flow

2007 ◽  
Author(s):  
James Menart ◽  
Mike McFarland ◽  
Kelly Cambell
Keyword(s):  
Flat Plate ◽  
Surface Pressure ◽  
Plasma Arc ◽  
Pressure Changes

Full 3-D Unsteady Numerical Simulation of Control Stage in Partial Admission Turbine

2015 ◽  
Vol 741 ◽  
pp. 509-512
Author(s):  
Guo Ping Li ◽  
Ke Ke Gao ◽  
Ke Yang ◽  
Yong Hui Xie
Keyword(s):  
Numerical Simulation ◽  
Surface Pressure ◽  
Flow Parameters ◽  
Control Stage ◽  
Air Turbine ◽  
Unsteady Surface Pressure ◽  
Partial Admission ◽  
Unsteady Numerical Simulation ◽  
Pressure Changes ◽  
Mixing Losses

The unsteady flow parameters in control stage of partial admission are analyzed in details with full 3-D numerical simulation. The full annulus structure of air turbine in partial admission is modeled due to the unsymmetrical geometry. The partial admission is accomplished through the inlet blocked using segmental arc. The unsteady surface pressure changes of eight blades in the transition regions which demonstrate the power output ability are presented. That the entropy rise associated with the losses at different cross mainly caused by mixing losses and flow separation in partial admission is analyzed to estimate the efficiency distribution.

Mass transfer between a plane surface and an impinging turbulent jet: the influence of surface-pressure fluctuations

1982 ◽  
Vol 119 ◽  
pp. 91-105 ◽  
Author(s):  
K. Kataoka ◽  
Y. Kamiyama ◽  
S. Hashimoto ◽  
T. Komai
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Flat Plate ◽  
Stagnation Point ◽  
Surface Pressure ◽  
Velocity Gradient ◽  
Large Scale ◽  
Pressure Fluctuations ◽  
Wall Region ◽  
Local Measurement

Local measurement of the mass-transfer rate and velocity gradient when an axisymmetric jet impinges on a flat plate was carried out using an electrochemical technique. Local measurement of the surface pressure on the flat plate was carried out separately using piezoelectric pressure transducers. The stagnation-point mass-transfer coefficient reaches a maximum when the flat plate is placed at 6 nozzle diameters from a convergent nozzle. It has been confirmed that the mass transfer to the flat plate for a high Schmidt number is greatly enhanced owing to the velocity-gradient disturbances in the wall region of the boundary layer, while the momentum transfer is insensitive to such disturbances. The relative intensity of the velocity-gradient fluctuations on the wall has an extremely large value at and near to the stagnation point, and decreases downstream, approaching a large constant value.These velocity-gradient disturbances are not due to the usual interaction of Reynolds stress with the shear stress of the mean flow, but are due to the interaction with the surface-pressure fluctuations converted from the velocity fluctuations of the oncoming jet.The three co-ordinate dimensions of large-scale eddies are calculated from the auto- and spatial correlations of the surface-pressure fluctuations. It is considered that such large-scale eddies play an important role in the production of a velocity-gradient disturbance in the wall region of the boundary layer from the velocity turbulence of the approaching jet.

The Wake of Self-Propelled and Over-Thrusted Slender Bodies Near a Simulated Free Surface

1988 ◽  
Vol 32 (01) ◽  
pp. 70-79
Author(s):  
W. Neu ◽  
P. Mitra ◽  
J. Schetz
Keyword(s):  
Free Surface ◽  
Flat Plate ◽  
Axisymmetric Body ◽  
The Self ◽  
Spectral Measurements ◽  
Mean Flow ◽  
Flow Parameters ◽  
Slender Bodies ◽  
Pressure Changes ◽  
Far Wake

Measurements were performed in the turbulent wake of a propeller-driven axisymmetric body with a plane of symmetry. A flat plate strut was attached to the upper surface of the axisymmetric body, giving a configuration like that of a SWATH-type ship, with the free surface replaced by the plane of symmetry. All mean flow and turbulent flow parameters were measured at three streamwise stations. The measurements were performed for the self-propelled condition and 100 percent over-thrust condition. In the far wake, the center of the wake was found to migrate towards the plane of symmetry. Some interactions were noted between the wakes of the propeller-driven axisymmetric body and that of the flat plate strut—yielding lower axial velocities, higher turbulence intensities and larger static pressure changes compared to regions free of such interference. Comparisons of these effects in the self-propelled case, 100 percent over-thrust case and a previous unpropelled case are given. Spectral measurements were also performed in both near-wake and far-wake regions.

Verification and Validation Studies for Laminar Hypersonic Flow Over a Blunted Cone and a Flat Plate

2006 ◽  
Author(s):  
S. Gokaltun ◽  
P. V. Skudarnov ◽  
C. X. Lin ◽  
Hugh Thornburg
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Flat Plate ◽  
Hypersonic Flow ◽  
Surface Pressure ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Numerical Results ◽  
Verification And Validation

In this paper, verification and validation analysis for laminar hypersonic flow fields is presented. The simulations include a Mach 8 flow of calorically perfect gas over a spherically blunted cone and a Mach 14 flow over a flat plate. Numerical results were obtained using the finite volume method on structured grids. The verification of the numerical solutions was performed by calculating the Grid Convergence Index (GCI) for both test cases. A set of three different grids is used to calculate the discretization uncertainty, where each grid was generated by doubling the number of cells in each direction of the coarser grid. The value of GCI allows calculating the observed order of accuracy of the numerical method for local values of surface pressure at various points and the net drag force for the blunted cone case and for the local heat transfer coefficient for the flat plate case. The error band was observed to be 2.4% for the surface pressure in the blunted cone problem and 0.5% for the heat transfer coefficient in the flat plate problem. Finally the numerical results were validated with experimental data using the local surface pressure measurements for the hypersonic cone and the local heat transfer coefficient measurements for the hypersonic flat plate.

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.

Design and Research of Wind Tunnel Test for Deflectable Nose

2013 ◽  
Vol 423-426 ◽  
pp. 2063-2067
Author(s):  
Bo Zhang ◽  
Shu Shan Wang ◽  
Meng Yu Cao ◽  
Yu Xin Xu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flat Plate ◽  
Surface Pressure ◽  
Wind Tunnel Test ◽  
Cost Effective ◽  
Trajectory Control ◽  
Attack Angle ◽  
Rubber Tube ◽  
Pressure Distributions

A wind tunnel test is designed to study aerodynamic effects of one individual rocket with deflectable nose. The test measures pressure with U-bend tube which is cost effective. Using rubber tubes in different lengths to measure pressure distributions of a flat-plate, and calculating how rubber tube affects the measurement, in order to modify the measured surface pressure of the nose. The surface pressure varies on different points while yawing angle and attack angle changes, the changing regularity could provide data for following numerical simulation and trajectory control.

Dynamic surface-pressure changes and their significance for weather forecasting

1954 ◽  
Vol 4 (3) ◽  
pp. 350-370 ◽  
Author(s):  
Stanislav Brandejs ◽  
Jaroslav Kopáček ◽  
Vojtěch Vítek ◽  
Otakar Zikmunda
Keyword(s):  
Surface Pressure ◽  
Weather Forecasting ◽  
Dynamic Surface ◽  
Pressure Changes
Sign in / Sign up

Export Citation Format

Share Document