Rotor Wake Mixing Effects Downstream of a Compressor Rotor

1981 ◽  
Author(s):  
A. Ravindranath ◽  
B. Lakshminarayana
Keyword(s):  
Shear Stresses ◽  
Flow Properties ◽  
Near Wake ◽  
Trailing Edge ◽  
Data Set ◽  
Rotor Wake ◽  
Compressor Rotor ◽  
Wake Interaction ◽  
Extensive Information ◽  
Three Components

An experimental study of rotor wake was conducted in the trailing-edge and near-wake regions of a moderately loaded compressor rotor blade using a rotating tri-axial hot-wire probe in a rotating frame of reference. The flow fieldwas surveyed very close to the trailing-edge as well as inside the annulus- and hub-wall boundary layers. The large amount of data acquired during this program has been analyzed to discern the decay effects as well as the span wise variation of three components of velocity, three components of intensities and three components of shear stresses. The data set also include extensive information on the variation of the flow properties downstream. The other derived quantities include wake momentum thickness and deviation angles at various span wise and downstream locations. These data are presented and interpreted, with emphasis on the downstream mixing as well as endwall-wake interaction effects.

Rotor Wake Mixing Effects Downstream of a Compressor Rotor

1982 ◽  
Vol 104 (1) ◽  
pp. 202-210 ◽  
Author(s):  
A. Ravindranath ◽  
B. Lakshminarayana
Keyword(s):  
Shear Stresses ◽  
Flow Properties ◽  
Near Wake ◽  
Trailing Edge ◽  
Data Set ◽  
Rotor Wake ◽  
Compressor Rotor ◽  
Wake Interaction ◽  
Extensive Information ◽  
Three Components

An experimental study of rotor wake was conducted in the trailing-edge and near-wake regions of a moderately loaded compressor rotor blade using a rotating triaxial hot-wire probe in a rotating frame of reference. The flow-field was surveyed very close to the trailing-edge as well as inside the annulus and hub-wall boundary layers. The large amount of data acquired during this program has been analyzed to discern the decay effects as well as the spanwise variation of three components of velocity, three components of intensities and three components of shear stresses. The data set also include extensive information on the variation of the flow properties downstream. The other derived quantities include wake momentum thickness and deviation angles at various spanwise and downstream locations. These data are presented and interpreted, with emphasis on the downstream mixing as well as endwall-wake interaction effects.

Three-Dimensional Turbulent Flow Field Downstream of a Single-Stage Axial Compressor Rotor

2000 ◽  
Author(s):  
Hongwei Ma ◽  
Haokang Jiang
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Mass Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Single Stage ◽  
Suction Surface ◽  
Trailing Edge ◽  
Rotor Wake ◽  
Compressor Rotor

This paper reports an experimental investigation of the three-dimensional turbulent flow downstream of a single-stage axial compressor rotor. The flow fields were measured at two axial locations in the rotor-stator gap at different mass-flow conditions. Both hot-wire probe and fast-response pressure probe were employed to survey the flow structure. At the design condition, substantial flow blockage, turbulence, loss and aerodynamic noise mainly occur in the tip mid-passage, the rotor wake and at the hub corner of the suction surface. The radial component is the highest of the three turbulence intensities at 15% axial chord downstream of the trailing edge. With the flow downstream, the radial turbulence components decay fast. Interactions of the tip leakage vorticities and the rotor wake are found at 30% axial chord downstream of the trailing edge. With the mass-flow decrease, the turbulence intensities and shear stresses become stronger, while the radial components increase fast. The flow separation and tangential migration of the low-energy fluids at the tip corner of the suction surface play an important role in the tip flow field at a low mass-flow condition.

Structure and Decay Characteristics of Turbulence in the Near and Far-Wake of a Moderately Loaded Compressor Rotor-Blade

1981 ◽  
Vol 103 (1) ◽  
pp. 131-140 ◽  
Author(s):  
A. Ravindranath ◽  
B. Lakshminarayana
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Three Dimensional ◽  
Inlet Guide Vane ◽  
Near Wake ◽  
Trailing Edge ◽  
Free Stream Turbulence ◽  
Compressor Rotor ◽  
Wake Turbulence ◽  
Far Wake

The wake of a turbomachinery rotor-blade is turbulent, highly three-dimensional, and nonisotropic with appreciable curvature in the trailing-edge and near-wake regions. The characteristics of the turbulence vary considerably with radius, blade loading, free-stream turbulence, Reynolds number, and the rotor-blade geometry. This paper is concerned with the turbulence properties of a moderately loaded compressor blade, particularly near the blade trailing-edge. The tangential variation of the axial, tangential and radial intensities and stresses across the wake, as well as their decay characteristics were measured with a tri-axial hot-wire probe in the rotor frame of reference. The decay of intensities and stresses were found to be very rapid in the trailing-edge and near-wake regions and slow in the far-wake region. The effects of inlet-guide-vane and the hub-wall boundary layers on the rotor wake turbulence spectra are also discussed. Similarity rules for the three components of intensity are also derived and presented in this paper.

scholarly journals New administrative data on welfare dynamics in Germany: the Sample of Integrated Welfare Benefit Biographies (SIG)

2020 ◽  
Vol 54 (1) ◽  
Author(s):  
Kerstin Bruckmeier ◽  
Sandra Dummert ◽  
Philipp Grunau ◽  
Katrin Hohmeyer ◽  
Torsten Lietzmann
Keyword(s):  
Labour Market ◽  
Unemployment Benefit ◽  
Welfare Benefit ◽  
Welfare Receipt ◽  
Data Set ◽  
Employment Agency ◽  
Integrated Employment ◽  
Labour Market Participation ◽  
Extensive Information ◽  
Household Members

Abstract The Sample of Integrated Welfare Benefit Biographies (SIG) is a new administrative longitudinal microdata set representative of recipients of Germany’s main welfare programme, the Unemployment Benefit II (UB II, Arbeitslosengeld II). The data set contains detailed longitudinal information on welfare receipt and labour market activities, and hence enables researchers to analyse the dynamics of benefit receipt, income and employment. A distinct feature of the SIG is that it provides information not only for individual benefit recipients but also for family members, including children and partners. This is possible because eligibility for UB II benefits depends on the household structure, and it is means-tested on household income. In addition to socio-demographic and regional information, the SIG contains extensive information on the employment biographies of benefit recipients and their household members from the Integrated Employment Biographies (IEB) of the Institute for Employment Research (IAB). This allows researchers to examine the interaction between labour market participation and benefit receipt. The SIG is available to researchers at the Research Data Centre (FDZ) of the Federal Employment Agency (BA) at the IAB.

Unsteady Numerical Simulation of Shock Systems in Vaneless Counter-Rotating Turbine

2005 ◽  
Author(s):  
Huishe Wang ◽  
Qingjun Zhao ◽  
Xiaolu Zhao ◽  
Jianzhong Xu
Keyword(s):  
Numerical Simulation ◽  
Mach Number ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Nozzle Design ◽  
Suction Surface ◽  
Rotor Wake ◽  
Wake Interaction ◽  
Unsteady Numerical Simulation ◽  
Almost All

A detailed unsteady numerical simulation has been carried out to investigate the shock systems in the high pressure (HP) turbine rotor and unsteady shock-wake interaction between coupled blade rows in a 1+1/2 counter-rotating turbine (VCRT). For the VCRT HP rotor, due to the convergent-divergent nozzle design, along almost all the span, fishtail shock systems appear after the trailing edge, where the pitch averaged relative Mach number is exceeding the value of 1.4 and up to 1.5 approximately (except the both endwalls). A group of pressure waves create from the suction surface after about 60% axial chord in the VCRT HP rotor, and those waves interact with the inner-extending shock (IES). IES first impinges on the next HP rotor suction surface and its echo wave is strong enough and cannot be neglected, then the echo wave interacts with the HP rotor wake. Strongly influenced by the HP rotor wake and LP rotor, the HP rotor outer-extending shock (OES) varies periodically when moving from one LP rotor leading edge to the next. In VCRT, the relative Mach numbers in front of IES and OES are not equal, and in front of IES, the maximum relative Mach number is more than 2.0, but in front of OES, the maximum relative Mach number is less than 1.9. Moreover, behind IES and OES, the flow is supersonic. Though the shocks are intensified in VCRT, the loss resulted in by the shocks is acceptable, and the HP rotor using convergent-divergent nozzle design can obtain major benefits.

Measurements of real non-Newtonian response for liquid lubricants under moderate pressures

2001 ◽  
Vol 215 (3) ◽  
pp. 223-233 ◽  
Author(s):  
S Bair
Keyword(s):  
Numerical Simulation ◽  
Kinetic Theory ◽  
Simple Shear ◽  
Pressure Dependence ◽  
Shear Stresses ◽  
Current Interest ◽  
Flow Properties ◽  
Power Law Fluid ◽  
Temperature And Pressure

A thorough characterization of all viscous flow properties relevant to steady simple shear was carried out for five liquid lubricants of current interest to tribology. Shear stresses were generated to values significant to concentrated contact lubrication. Two types of non-Newtonian response were observed: shear-thinning as a power-law fluid and near rate-independence. Functions and parameters were obtained for the temperature and pressure dependence of the viscosity and of the time constant for the Carreau-Yasuda equation. Results are consistent with free volume and kinetic theory, but directly contradict many assumptions currently utilized for numerical simulation and for extracting rheological properties from contact measurements.

scholarly journals Rotor wake interaction with separated flow

1993 ◽  
Vol 18 (3-4) ◽  
pp. 73-87 ◽  
Author(s):  
N.M Komerath ◽  
J.M Kim ◽  
S.G Liou
Keyword(s):  
Separated Flow ◽  
Rotor Wake ◽  
Wake Interaction

Effects of Flow Properties of Lithium Soap Greases on Bearing Torque

2019 ◽  
Vol 823 ◽  
pp. 123-127
Author(s):  
Norifumi Miyanaga ◽  
Mitsumi Nihei ◽  
Jun Tomioka
Keyword(s):  
Apparent Viscosity ◽  
Small Amplitude ◽  
Shear Stresses ◽  
Flow Properties ◽  
Small Amplitude Oscillatory Shear ◽  
Small Ball ◽  
Shear Rates ◽  
Lithium Soap ◽  
Viscoelastic Behaviors ◽  
Plate Type

This study describes the influence of flow properties of lithium soap greases on torque of small ball bearings. Three types of greases with different worked penetration were tested in this study. Their rheological properties are revealed by a cone plate type rheometer. Shear stresses under various shear rates are fitted with the Herschel-Bulkley equation. In addition, viscoelastic behaviors of the greases are measured by small amplitude oscillatory shear. The crossover stress that means the shear stress at G’=G” is obtained for the greases. Then, the bearing torque when three types of greases are used as a lubricant is measured. As the results, the grease with higher crossover stress shows the lower bearing torque regardless of that it has larger apparent viscosity. On the other hand, the grease with lower crossover stress shows the higher bearing torque regardless of that it has lower apparent viscosity. These results imply that the channeling state appears in the grease with higher crossover stress while the churning state appears in the grease with lower crossover stress.

Near-Wake Flow Dynamics Resulting from Trailing Edge Spanwise Perturbation

2008 ◽  
Author(s):  
L Doddipatla ◽  
H Hangan ◽  
V Durgesh ◽  
J Naughton
Keyword(s):  
Flow Dynamics ◽  
Wake Flow ◽  
Near Wake ◽  
Trailing Edge
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