Self-Aligning Hot-Wire Probe

1967 ◽  
Vol 71 (681) ◽  
pp. 657-658 ◽  
Author(s):  
A. D. Bond ◽  
A. M. Porter
Keyword(s):  
Constant Temperature ◽  
Two Dimensional ◽  
Servo Motor ◽  
Hot Wire ◽  
Turbulence Measurements ◽  
Wire Probe ◽  
Two Dimensional Flow ◽  
The Wire ◽  
Single Constant ◽  
Stream Direction

Summary:—This note describes how a single constant temperature hot wire may be used for measurements of direction, velocity and turbulence in a two-dimensional flow. The wire probe is rotated by a servo motor which automatically sets the wire with its axis either in the stream direction or normal to the flow. The accuracy of setting the wire in the direction of the stream is about , and across the stream is about 1°. If the higher accuracy is demanded the velocity and turbulence measurements require a second setting of the probe, at 90° to the previous one. When less precision is acceptable, the angle, velocity and turbulence measurements may be taken at the single setting, normal to the stream.

Calibration of Constant-Temperature Hot-Wire Anemometers at Low Velocities in Water with Variable Fluid Temperature

1972 ◽  
Vol 94 (1) ◽  
pp. 17-22 ◽  
Author(s):  
K. Hollasch ◽  
B. Gebhart
Keyword(s):  
Experimental Study ◽  
Natural Convection ◽  
Constant Temperature ◽  
Fluid Temperature ◽  
Hot Wire ◽  
Temperature Variations ◽  
Wire Probe ◽  
Temperature Mode

Calibration of hot-wire probes operated in a constant-temperature mode in water at low velocities is discussed. Operation under circumstances where natural convection effects are important is considered. A method of calibrating a constant-temperature hot-wire probe for variations in fluid temperature is presented. The method consists of varying wire overheat during calibration at a constant fluid temperature. A relation is derived analytically relating anemometer output with a variable overheat resistance to anemometer output with fluid temperature variations. An experimental study to verify the analysis is presented.

Shear Effects in Hot-Wire Measurements

1976 ◽  
Vol 98 (4) ◽  
pp. 771-773 ◽  
Author(s):  
Ronald M. C. So
Keyword(s):  
Lift Force ◽  
Viscous Sublayer ◽  
Diameter Ratio ◽  
Two Dimensional ◽  
Wire Length ◽  
Hot Wire ◽  
True Position ◽  
Shear Gradient ◽  
Shear Effects ◽  
The Wire

When a circular cylinder is placed in a two-dimensional shear flow, a lift force is experienced by the cylinder. In the case of hot-wire measurements in the viscous sublayer, this will give rise to a displacement of the wire from its true position. The resultant measurements are found to be in error if the wire length to diameter ratio is > 300 and the shear gradient of the flow is large.

Dynamic and Static Characteristics Analysis Study of Hot-Wire Probe in Constant Temperature Model

2013 ◽  
Vol 278-280 ◽  
pp. 735-742
Author(s):  
Qing Yan Wei ◽  
Tian Hong Zhang
Keyword(s):  
Heat Conduction ◽  
Constant Temperature ◽  
Temperature Model ◽  
Static Characteristics ◽  
Hot Wire ◽  
Wire Probe ◽  
Balance Principle ◽  
Characteristics Analysis ◽  
Control Circuits ◽  
Improved Design

Lumped and distributed dynamic/static models of constant temperature hot-wire probe are established according to heat balance principle. Dynamic and static characteristics of hot-wire probe are analyzed in terms of hot-wire probe sizes, control circuit parameters and flow velocity.Simulation results show that reliability and stability of the hot-wire probe depend on bias voltage.The dynamic and static characteristics of hot-wire probe refly on the ratio of length to diameter ratio crucially.Once the ratio exceeds 300, heat conduction terminal loss can be ignored. When over-heating ratio of hot- wire or flow velocity increases, heat conduction terminal loss can be omitted as well .Besides frequency response of hot-wire probe can be improved simultaneously.The above conclusions can provide guidance in the improved design for hot-wire probe and its control-circuits.

scholarly journals Characteristic Factors of a Compressor Rotor in Comparison With Two-Dimensional Cascade Data

1986 ◽  
Author(s):  
H. Pfeil ◽  
J. Sieber
Keyword(s):  
Rotor Blade ◽  
Axial Flow ◽  
Processing System ◽  
Two Dimensional ◽  
Hot Wire ◽  
Data Processing System ◽  
Wire Probe ◽  
Compressor Rotor ◽  
Profile Losses ◽  
Flow Compressor

The performance of a blade in an axial-flow compressor rotor is compared with the performance in a two-dimensional cascade. Using a stationary hot-wire probe and a data processing system the velocity profiles across the rotor wakes were measured in order to calculate the profile losses and the lift coefficients of the rotor blade.

The Use of a Hot-Wire Anemometer in Turbulent Flow

1967 ◽  
Vol 71 (679) ◽  
pp. 511-513 ◽  
Author(s):  
B. J. Hoole ◽  
J. R. Calvert
Keyword(s):  
Turbulent Flow ◽  
Flow Direction ◽  
Unsteady Flows ◽  
Wire Length ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Local Flow ◽  
The Wire ◽  
Stream Direction

The hot-wire anemometer is one of the few instruments which can be used to make velocity measurements in turbulent and unsteady flows. However, the probe supporting the wire inevitably interferes with the local flow and it has been found that the effect of this interference on the reading of the anemometer varies considerably as the orientation of the probe to the flow direction is changed (the wire itself being maintained in the same direction). This leads to errors in any measurements taken where the instantaneous local flow direction differs significantly at any time from the direction for which the anemometer was calibrated. Such errors are quite separate from, and in addition to, errors due to finite wire length, incidence of the wire to the local stream direction, etc.

Turbulence Measurements With Symmetrically Bent V-Shaped Hot-Wires. Part 2: Measuring Velocity Components and Turbulent Shear Stresses

1988 ◽  
Vol 110 (3) ◽  
pp. 270-274 ◽  
Author(s):  
M. Hishida ◽  
Y. Nagano
Keyword(s):  
Flow Field ◽  
Velocity Component ◽  
Turbulent Shear ◽  
Shear Stresses ◽  
Wall Surface ◽  
Hot Wire ◽  
Turbulence Measurements ◽  
Straight Wire ◽  
Hot Wires ◽  
The Wire

An analysis of the response of a V-shaped hot-wire to velocity component fluctuations is presented. A V-shaped hot-wire works in the same manner as a conventional inclined straight wire. The great differences are: the V-shaped wire is less sensitive to the w component of velocity; the V-shaped wire can be supported just like a cantilever, and thus the wire may be brought closer to the wall until it touches the wall surface, whereas an inclined straight wire is kept away from the wall by the supports, and a probe body distorts the flow field.

An Experimental Study of the Secondary Flow in a Curved Rectangular Channel

1980 ◽  
Vol 102 (1) ◽  
pp. 92-96 ◽  
Author(s):  
M. D. Kelleher ◽  
D. L. Flentie ◽  
R. J. McKee
Keyword(s):  
Secondary Flow ◽  
Rectangular Channel ◽  
Wave Number ◽  
Two Dimensional ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Dean Number ◽  
Wire Probe ◽  
Vortex Pattern ◽  
Secondary Motion

The Taylor-Gortler vortex pattern in a curved rectangular channel of high aspect ratio has been examined using hot wire anemometry. Using a two dimensional traversing mechanism, velocity surveys have been made at several radial locations across the channel for several values of Dean number. The velocity measurements show that the periodic secondary motion undergoes a phase shift as the hot wire probe crosses the midplane between the concave and convex walls. The measurements also indicate that the secondary flow wave number is constant over the range of Dean numbers examined. Complementary flow visualization photographs of the secondary motion have also been obtained.

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