An Explicit Non-Real Time Data Reduction Method of Triple Sensors Hot-Wire Anemometer in Three-Dimensional Flow

1988 ◽  
Vol 110 (2) ◽  
pp. 110-119 ◽  
Author(s):  
Y. T. Chew ◽  
R. L. Simpson
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Computation Time ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Time Data ◽  
Three Dimensional Flow ◽  
Mean Velocity ◽  
Dimensional Flow ◽  
The Mean

An explicit non-real time method of reducing triple sensor hot-wire anenometer data to obtain the three mean velocity components and six Reynolds stresses, as well as their turbulence spectra in three-dimensional flow is proposed. Equations which relate explicitly the mean velocity components and Reynolds stresses in laboratory coordinates to the mean and mean square sensors output voltages in three stages are derived. The method was verified satisfactorily by comparison with single sensor hot-wire anemometer measurements in a zero pressure gradient incompressible turbulent boundary layer flow. It is simple and requires much lesser computation time when compared to other implicit non-real time method.

Turbulence Measurements Near the Stern of a Ship Model

1984 ◽  
Vol 28 (03) ◽  
pp. 186-201
Author(s):  
Lennart Löfdahl ◽  
Lars Larsson
Keyword(s):  
Boundary Layer ◽  
Strong Influence ◽  
Three Dimensional ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Calculation Methods ◽  
Mean Velocity ◽  
Ship Model ◽  
The Mean ◽  
Stress Profiles

An experimental investigation in which Reynolds stress profiles were measured in the thick three-dimensional turbulent boundary layer at the stern of a ship model has been carried out. The measurements were performed using a specially developed hot-wire technique in which the mean velocity component perpendicular to the surface was considered. A large number of results are given in diagrams, and an error estimation for the different Reynolds stresses is presented. Efforts have been made, when positioning the measured turbulence profiles, to enable future development of calculation methods based on these results. The measured profiles have revealed a strong influence of streamline convergence (divergence) on the Reynolds stresses. Also, the effects of wall curvature are of importance, and since most parts of the investigated region have a convex curvature the average level of the stresses is reduced.

Hot Wire Measurements at the Exit of a Centrifugal Compressor Impeller

1979 ◽  
Vol 193 (1) ◽  
pp. 341-347
Author(s):  
A. Goulas ◽  
R. C. Baker
Keyword(s):  
Centrifugal Compressor ◽  
Magnetic Tape ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Mean Velocity ◽  
Isentropic Flow ◽  
Compressor Impeller ◽  
The Mean

Hot wire measurements at the exit of a small centrifugal compressor impeller are reported. Three different hot wire readings were obtained and stored on a magnetic tape for each point by gating the analogue hot wire signal with a pulse which indicated circumferential position. The combination of the three readings yielded the mean velocity and some Reynolds stresses at each point. The measurements show a ‘jet-wake’ profile towards the shroud and ‘isentropic’ flow near the hub.

A Three-Dimensional Analysis of Rotor Wakes

1972 ◽  
Vol 23 (4) ◽  
pp. 285-300 ◽  
Author(s):  
C E Whitfield ◽  
J C Kelly ◽  
B Barry
Keyword(s):  
Dimensional Analysis ◽  
Constant Temperature ◽  
Three Dimensional ◽  
Axial Flow ◽  
Visual Presentation ◽  
Hot Wire ◽  
Three Dimensional Flow ◽  
Dimensional Flow

SummaryMany investigators have studied the aerodynamics of axial flow turbomachinery but none has produced a complete map of the three-dimensional flow behind a rotor row. This is of considerable interest to the aero-acoustician. A system is described which uses a constant temperature hot-wire anemometer to analyse the flow behind such a rotor. Although much information may be extracted by using the technique, its interpretation depends to a large extent on its form of presentation. An analysis of the flow behind a research fan is used as a means of discussing various forms of visual presentation.

Measurement of the Reynolds stresses and the mean-flow field in a three-dimensional pressure-driven boundary layer

1982 ◽  
Vol 119 ◽  
pp. 121-153 ◽  
Author(s):  
Udo R. Müller
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Flow Field ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Mean Velocity ◽  
Flow Acceleration ◽  
The Mean

An experimental study of a steady, incompressible, three-dimensional turbulent boundary layer approaching separation is reported. The flow field external to the boundary layer was deflected laterally by turning vanes so that streamwise flow deceleration occurred simultaneous with cross-flow acceleration. At 21 stations profiles of the mean-velocity components and of the six Reynolds stresses were measured with single- and X-hot-wire probes, which were rotatable around their longitudinal axes. The calibration of the hot wires with respect to magnitude and direction of the velocity vector as well as the method of evaluating the Reynolds stresses from the measured data are described in a separate paper (Müller 1982, hereinafter referred to as II). At each measuring station the wall shear stress was inferred from a Preston-tube measurement as well as from a Clauser chart. With the measured profiles of the mean velocities and of the Reynolds stresses several assumptions used for turbulence modelling were checked for their validity in this flow. For example, eddy viscosities for both tangential directions and the corresponding mixing lengths as well as the ratio of resultant turbulent shear stress to turbulent kinetic energy were derived from the data.

scholarly journals Three-Dimensional Flow Analysis over Canard Configuration in Turbulence Model

2022 ◽  
pp. 112-117
Author(s):  
L V S S Lohitasya Varun ◽  
Y. D. Dwivedi
Keyword(s):  
Flow Field ◽  
Real Time ◽  
Turbulence Model ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Model Solution ◽  
Field Analysis ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Flow Field Analysis

The canard has been seen as an ominous aerodynamic object for ages this paper is to shed some more light on the effects of canard configuration on the aircraft’s wings. This flow-field analysis is thus being done using a turbulence model solution to take into the effects of a real-time environment where the vortices from the canard are captured more accurately. The analysis has been done meticulously and made to be as error-free as possible under the guidance of Dr. Yagya Dutta Dwivedi.

The Three-Dimensional Flow and Blade Wake in an Axial Plane Downstream of an Axial Compressor Rotor

1978 ◽  
Author(s):  
P. Kool ◽  
J. DeRuyck ◽  
Ch. Hirsch
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Plane ◽  
Hot Wire ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Wall Boundary Layer ◽  
Compressor Rotor ◽  
Three Dimensional Finite Element ◽  
Flow Variables

The three-dimensional flow field has been measured in an axial plane downstream of a low speed axial compressor rotor with a rotated single slanted hot wire. A method is described which allows one to calculate three mutually perpendicular velocity components from hot-wire data, and use is made of the technique of periodic sampling and averaging to extract the pitchwise fluctuating flow from the stationary hot-wire signals. These data contain useful information. The radial distribution of the pitchwise averaged flow variables is compared with classical pneumatic measurements and with the results of a quasi three-dimensional finite-element calculation and a three-dimensional end-wall boundary layer calculation. Finally, the wake characteristics are given and a simple correlation is presented which allows one to determine the wake velocity defect from a single wake shape factor.

A fast simple hot-wire method of determining the mean velocity vector of complex three-dimensional flows

1996 ◽  
Vol 20 (5) ◽  
pp. 398-400 ◽  
Author(s):  
L. Löfdahl ◽  
B. Johansson ◽  
C. Ljus ◽  
P. Ålleving
Keyword(s):  
Velocity Vector ◽  
Three Dimensional ◽  
Hot Wire ◽  
Mean Velocity ◽  
Wire Method ◽  
The Mean

Homogeneity of turbulence generated by static-grid structures

2010 ◽  
Vol 654 ◽  
pp. 473-500 ◽  
Author(s):  
Ö. ERTUNÇ ◽  
N. ÖZYILMAZ ◽  
H. LIENHART ◽  
F. DURST ◽  
K. BERONOV
Keyword(s):  
Reynolds Number ◽  
Velocity Field ◽  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Uniform Grid ◽  
Reynolds Stresses ◽  
Hot Wire ◽  
Mean Velocity ◽  
Wide Range ◽  
The Mean

Homogeneity of turbulence generated by static grids is investigated with the help of hot-wire measurements in a wind-tunnel and direct numerical simulations based on the Lattice Bolztmann method. It is shown experimentally that Reynolds stresses and their anisotropy do not become homogeneous downstream of the grid, independent of the mesh Reynolds number for a grid porosity of 64%, which is higher than the lowest porosities suggested in the literature to realize homogeneous turbulence downstream of the grid. In order to validate the experimental observations and elucidate possible reasons for the inhomogeneity, direct numerical simulations have been performed over a wide range of grid porosity at a constant mesh Reynolds number. It is found from the simulations that the turbulence wake behind the symmetric grids is only homogeneous in its mean velocity but is inhomogeneous when turbulence quantities are considered, whereas the mean velocity field becomes inhomogeneous in the wake of a slightly non-uniform grid. The simulations are further analysed by evaluating the terms in the transport equation of the kinetic energy of turbulence to provide an explanation for the persistence of the inhomogeneity of Reynolds stresses far downstream of the grid. It is shown that the early homogenization of the mean velocity field hinders the homogenization of the turbulence field.

Three-Dimensional Flow and Mixing in an Axial Flow Compressor With Different Rotor Tip Clearances

1991 ◽  
Author(s):  
Akira Goto
Keyword(s):  
Velocity Fluctuation ◽  
Three Dimensional ◽  
Axial Flow ◽  
Tip Clearance ◽  
Small Scale ◽  
Hot Wire ◽  
Three Dimensional Flow ◽  
Axial Flow Compressor ◽  
Dimensional Flow ◽  
Flow Compressor

The effect of difference in rotor tip clearance on the mean flow fields and unsteadiness and mixing across a stator blade row were investigated using hot-wire anemometry, pressure probes, flow visualization and the ethylene tracer-gas technique on a single stage axial flow compressor. The structure of the three-dimensional flow fields was discussed based on results of experiments using the 12-orientation single slanted hot-wire technique and spectrum analysis of velocity fluctuation. High-pass filtered measurements of turbulence were also carried out in order to confirm small-scale velocity fluctuation which is more realistically referred to as turbulence. The spanwise distribution of ethylene gas spreading, estimated by the measured small-scale velocity fluctuation at the rotor exit, agreed quite well with that which was experimentally measured. This fact suggests the significant role of turbulence, generated within the rotor, in the mixing process across the downstream stator. The value of the maximum mixing coefficient in the tip region was found to increase linearly as the tip clearance became enlarged, starting from the value at midspan.

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