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Investigation of separated flow around a Curved Air Intake

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Advances in Manufacturing 1997年第3期1卷 221-225页

作者：翁培奋 Shanghai Institute of Applied Math. & Mech Shanghai University Shanghai

This paper prcsents an investigation of two-dimensional separated flow in and around a submerged curved intake by experiment and computation. The eniptic Navier-Stokes equations are employed which are discreted in body-fitted coordinate system by the SIMPLE method. The results show that the flow separation exists near and behind the inlet and the duct flow is distorted. Comparison between the computational and experimental data is fairly satisfactory.

关键词： inlet flow distortion separated flow numerical analysis

Numerical Simulation and Experimental Investigation of 3 D separated flow Field around a Blunt Body

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Advances in Manufacturing 1999年第3期3卷 259-262页

作者： Doctoral Candidate: TAN Fa sheng Advisor: Prof. DAI Shi qiang Prof. WENG Pei fen (Shanghai Institute of Appllied Mathematics and Mechanics, Shanghai University) Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai China

To study the effects of factors such as electromagnetic field and electron temperature on the ion extraction characteristics (extraction time, collision loss ratio) in atomic vapor laser isotope separation (AVLIS), 2 D electron equilibrium model was used to analyze and simulate the ion extraction process. The collisions between particles mainly considered charge exchanges between isotopic ions and atoms, which were treated by using cross section. The results show that the electric field and electron temperature have significant effects on the ion extraction characteristics: the stronger the electric field is, the higher the electron temperature is; the shorter the extraction time is, the less the collision loss ratio is, and moderate constant magnetic field has few effects on them. Key words atomic vapor laser isotope separation (AVLIS); ion extraction; charge exchange cross section; collision loss ratio 

关键词： blunt body separated flow numerical simulation NS equations flow visualization LDV experiment

A Study of 2D separated Cascade flow at Large Angles of Attack Using Euler Equations

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Journal of Thermal Science 1992年第2期1卷 90-97页

作者： YeDajun LiuWeidong 等 DepartmentofThermalEngineering TsinghuaUniversityBeijing100084China DepartmentofThermalEngineering

This paper presents a numerical simulation method developed for separated flow in cascades using the Euler equations and demonstrates the feasibility of this ***'s two-steps explicit finite difference scheme is used to discretize the equations in conservation form,and the artificial viscosity is added to the dis- cretized inviscid equations by means of the self-adapted filter *** initial separation boundary is given according to simple experimental *** numerical simulation results including subsonic and transonic turbine cascades flow with or without separation show that the fundamental idea of this numerical method is reasonable and *** present study indicates that for solving certain engineering problems it is a simple and effective tool for adding some viscosity corrections to inviscid flow model,especially the current when the Navier-Stokes equations have not been solved very effectively for various complicated flows in turbomachinery.

关键词： separated flow Euler equations artificial viscosity initial separation boundary turbine cascade numerical simulation self-adapted filter technique

INVESTIGATION OF PULSED-WIRE TECHNIQUE FOR WALL PARAMETERS MEASUREMENT IN separated flowS

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Chinese Journal of Aeronautics 1997年第2期10卷 98-103页

作者： Liao Yufeng, Xu Cheng(Mechanical Engineering Institute, Nanjing University of Scienceand Technology, Nanjing, 210094, China) Mechanical Engineering Institute Nanjing Univ. of Sci. and Technology Nanjing 210094 China

A pulsed-wire wall probe measurement system was developed in this paper,which can be used for measuring wall Parameters in separated flow- The operating princi-ple was described and the way of probe calibration was given. Wall parameters of back-ward-facing and forward-facing step flow were measured,and the wall nows structure andcharacters were revealed.

关键词： separated flow measurement pulse heating wall parameters pulsed-wire wall probe

New constitutive relation for eddy viscosity models

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航空动力学报 2016年第10期31卷 2485-2492页

作者： JIANG Li-jun GAO Ge Hunan Aviation Powerplant Research Institute Aero Engine Corporation of China School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

A new turbulent constitutive relation was directly derived from Boussinesqs hypothesis and mixing length theory,and then implemented in the standard k-ε *** performance of this constitutive relation was validated in zero pressure gradient flat-plate boundary layer flow,fully-developed turbulent channel flow and separated flow in a plane asymmetric *** investigation demonstrated that,this new constitutive relation gave very accurate results in the former two basic cases and provided significant improvement in prediction of separated and reattachment points in the plane asymmetric *** and reattachment points at x/H =7.5and 29 were calculated accurately in comparison to experimental results,and the static pressure coefficient of 0.82 was very close to large eddy simulation *** results are very encouraging but further verification and extensive application of the new constitutive relation to other two-equation eddy viscosity model are needed.

关键词： constitutive relation turbulence model flat-plate flow channel flow separated flow

Boundary layer separation control on a highly-loaded,low-solidity compressor cascade

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Journal of Thermal Science 2010年第2期19卷 97-104页

作者： Zhou Yang,Liu Huo-xing,Zou Zheng-ping and Ye Jian National Key Lab.on Aero-Engines,Aero-Engines Simulation Research Center,Beijing Univ.of Aero.& Astro.,Beijing 100083 National Key Lab. on Aero-Engines Aero-Engines Simulation Research Center Beijing Univ. of Aero. & Astro. Beijing China

separated flow can be effectively controlled through the management of blade boundary layer *** simulations on a highly-loaded,low-solidity compressor cascade indicate that combined blowing and suction flow control technique can significantly improve cascade performance,especially in increasing the cascade loading and static pressure ratio as well as decreasing the loss ***,it is more effective to improve cascade performance by blowing near leading edge on suction surface than suction near trailing *** the locations and flow rates of blowing and suction are major impact factors of this method to cascade *** to the baseline,the static pressure ratio increases by 15% and loss coefficient decreases by 80%,with a blowing fraction of 1.7% and a suction fraction of 1.38% of the inlet mass flow.

关键词： combined blowing and suction flow control compressor cascade boundary layer separated flow

AN EXPERIMENTAL STUDY OF flow AROUND A BIO-INSPIRED AIRFOIL AT REYNOLDS NUMBER 2.0×10~3

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Journal of Hydrodynamics 2012年第3期24卷 410-419页

作者： SHI Sheng-xian LIU Ying-zheng CHEN Jian-min Key Laboratory of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong University Shanghai 200240 China

The fluid flow around a bio-inspired airfoil with corrugated surfaces and its smooth counterpart at chord Reynolds number Re = 2.0×10^3. and different Angle-Of-Attack （AOA = 0°, 4°, 8° and 12°） were measured by using Particle Image Velocimetry （PIV）. The global characteristics of the fluid flow around two airfoils were analyzed by ensemble-averaged velocity field, distribution of reverse flow intermittency, and time-series flow visualizations. At AOA = 0°, no significant variation of the global flow patterns was recognized for both configurations. The statistical results of reverse flow intermittency results demonstrated that the protruding peaks of the corrugated airfoil delay flow separation occur at AOA = 4°. At large AOAs （8° and 12°）, however, the flow is massively separated in both configurations, the combination of large separation bubble above the corrugated airfoil and small recirculation zones in the upstream upper valley results in earlier separation of the flow. At AOA=8°, the wake region behind the corrugated airfoil is considerably shortened in comparison to the smooth one, indicating a remarkable reduction of the time-mean lift and drag forces, however, at AOA - 12°, the wake region behind the corrugated one is slightly larger than that behind the smooth one. For the case of AOA = 8° and 12°, the time-series flow visualizations demonstrate the intensified vortex shedding process of the corrugated airfoil, which would give rise to enhanced dynamic loading. Due to the fact that dragonfly wing is practically flexible, it is speculated that the wing structure of a gliding dragonfly might be sophisticatedly deformed in response to the periodic loading to reduce the drag.

关键词： corrugated airfoil separated flow Particle Image Velocimetry (PIV) dragonfly gliding flight

Improving Ambient Wind Environments of a Cross-flow Wind Turbine near a Structure by using an Inlet Guide Structure and a flow Deflector

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Journal of Thermal Science 2005年第3期14卷 242-248页

作者： Tadakazu TANINO Shinichiro NAKAO Genki UEBAYASHI Nagasaki Institute of Applied Science 536 Aba-machi Nagasaki 851-0193 JapanNagasaki Institute of Applied Science 536 Aba-machi Nagasaki 851-0193 JapanChoryo Engineering Co. Ltd. 5- 717-1 Fukahori-machi Nagasaki 851-0392 Japan

A cross-flow wind turbine near a structure was tested for the performance. The results showed that the performance of a cross-flow wind turbine near a structure was up to 30% higher than the one without a structure. In addition, we tried to get higher performance of a cross-flow wind turbine by using an Inlet Guide Structure and a flow Deflector. An Inlet Guide Structure was placed on the edge of a structure and a flow Deflector was set near a cross-flow wind turbine and can improve ambient wind environments of the wind turbine, the maximum power coefficients were about 15 to 40% higher and the tip speed ratio range showing the high power coefficient was wide and the positive gradients were steep apparently.

关键词： vertical axis wind turbine separated flow performance wind power

Imaging of supersonic flow over a double elliptic surface

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Chinese Physics B 2013年第11期22卷 369-375页

作者：张庆虎易仕和何霖朱杨柱陈植 College of Aerospace Science and Engineering National University of Defense Technology

The coherent structures of flow over a double elliptic surface are experimentally investigated in a supersonic low- noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering （NPLS） and particle image velocimetry （PIV） techniques. High spatiotemporal resolution images and velocity fields of both laminar and turbulent inflows over the test model are captured. Based on the time-correlation images, the spatial and temporal evolutionary characteristics of the coherent structures are investigated. The flow structures in the NPLS images are in good agreement with the velocity fluctuation fields by PIV. From statistically significant ensembles, spatial correlation analysis of both cases is performed to quantify the mean size and the orientation of coherent structures. The results indicate that the mean structure is elliptical in shape and the structural angles in the separated region of laminar inflow are slightly smaller than that of turbulent inflow. Moreover, the structural angles of both cases increase with their distance away from the wall.

关键词： coherent structures separated flow spatial correlation analysis supersonic flow