Calibrating a hot film anemometer for low velocity measurement in nonisothermal flow
Calibration data correlation for constant temperature hot film anemometer for low speed nonisothermal laminar air flow, using modified King law
Schmidt, F. W.↗
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Measurement of flow magnitude and direction by hot wire anemometer
Hot-wire anemometer measurements of incompressible fluid flow direction and velocity in pipes
Fox, R. W.↗
Anemometer with braking mechanism Patent
Anemometer with braking mechanism to prevent rotation of wind driven elements
Camp, D. W.↗
Measurement of flow magnitude and direction by hot wire anemometer
Incompressible planar fluid flow magnitude, direction and turbulent shear stress measurement by hot-wire anemometer
Fox, R. W.↗
A method for remote use of hot wire anemometer
Hot-wire anemometer remote operation, discussing coaxial cable length, terminal connection and bridge current
Finn, C. L.↗
Oscillating hot-wire anemometer
Performance analysis was made of oscillating hot-wire anemometer electrical output in gas stream. Advantages include no calibration and measurement of fluid direction as well as fluid speed.
Conley, J. M.↗
Flow field measurements around a Mars lander model using hot film anemometers under simulated Mars surface conditions
Results are presented from a wind-tunnel investigation of the flow field around a 0.45-scale model of a Mars lander. The tests were conducted in air at values of Reynolds number equivalent to those anticipated on Mars. The effects of Reynolds number equivalent to those anticipated on Mars. The effects of Reynolds number, model orientation with respect to the airstream, and the position of a dish-type antenna on the flow field were determined. An appendix is included which describes the calibration and operational characteristics of hot-film anemometers under simulated Mars surface conditions.
Greene, G. C.↗
Laser Doppler anemometer for water tunnel applications.
A laser Doppler anemometer for three-dimensional velocity measurement in liquids and gases under a wide range of laboratory conditions has been developed. The instrument is particularly well suited for water tunnel applications. It is portable, easily aligned, and inexpensive (excluding electronic units). It operates in backscatter or forward scatter mode. In both cases all optical components, including laser and photomultiplier, remain on a common base. The system has built-in traversing capability and an aiming device for visualizing the focal (test) point. Design details and representative velocity measurements are given.
Bossel, H. H.↗
An evlauation of the three-dimensional split-film anemometer for measurements of atmospheric turbulence
A three-dimensional split-film anemometer was tested in turbulent, as well as in nonturbulent flow downstream from a wind tunnel turbulence grid. The data obtained with this probe in the turbulence behind the grid, indicated that the measured turbulence intensities were somewhat lower than the intensity measured with the conventional hot-wire anemometry; a result of the finite dimensions of the sensor arrays. The probe yaw angle was determined to be accurate within three degrees. Statistical averages, determined by mean-wind direction and vertical and lateral directions were computed on the basis of the probe yaw angle.
Tieleman, H. W.↗
The response of a propeller anemometer to turbulent flow with the mean wind vector perpendicular to the axis of rotation
Determination of the properties of the system transfer function of the vertical-velocity propeller anemometer. A treatment of this problem is presented which is based on an analysis of estimates of the system transfer function derived from estimates of spectra calculated from time histories of indicated vertical velocity and on estimates of the associated input Eulerian vertical-velocity frequency spectra based on the hypothesis that instrument degradation of the Fourier components occurs in the inertial subrange.
Fichtl, G. H.↗
Some experiments in swirling flows: Detailed velocity measurements of a vortex breakdown using a laser Doppler anemometer
The results of an experimental study of spiraling flows in a slightly diverging, circular duct are reported. Seven types of flow disturbances were observed. In addition to the spiral and axisymmetric vortex breakdowns and the double helix mode, four other forms were identified and are reported. The type and axial location of the disturbance depended on the Reynolds and circulation numbers of the flow. Detailed velocity measurements were made by using a laser Doppler anemometer. Measurements made far upstream of any disturbance showed that the introduction of swirl resulted in the formation of a high axial velocity jet centered around the vortex center. A mapping of the velocity field of a so-called axisymmetric breakdown, formed at a Reynolds number of 2560, revealed that the recirculation zone is a two-celled structure, with four stagnation points on the vortex axis marking the axial extremes of the concentric cells. The dominant feature of the flow inside the bubble was the strong, periodic velocity fluctuations. Existing theoretical models do not predict the two-celled structure and the temporal velocity fluctuations that were observed.
Faler, J. H.↗
Metallic hot wire anemometer
A hot wire anemometer is described which has a body formed of heat resistant metal such as an alloy high in nickel content which supports a probe wire disposed in a V groove in the body. The V groove contains a high temperature ceramic adhesive that partially encompasses the downstream side of the probe wire. Mechanical and electrical connection to the probe wire is achieved through conductive support rods that are constructed of the same high temperature metal, insulation between the body and the conductor rods being provided by a coating of an oxide of the same material which coating is formed in situ. The oxide coating insulates the conductor rods from the body, mechanically fixes the conductors within the body, and maintains its integrity at elevated temperatures.
Lemos, F. R.↗
Method for making a hot wire anemometer and product thereof
A hot wire anemometer probe is described that includes a ceramic body supporting two conductive rods parallel to each other. The body has a narrow edge surface from which the rods protrude. A probe wire is welded to the rods and extends along the edge surface. A ceramic adhesive is used to secure the probe wire to the surface so that the probe wire is rigid. A method for fabricating the probe is also described in which the body is molded and precisely shaped by machining techniques before the probe wires are installed.
Milkulla, V.↗
An anemometer for measuring velocities on the .25 to 4.25 M/sec range
A vane type anemometer was developed as a secondary standard for the on site calibration of wind velocity sensors. The instrument outputs an electrical pulse for each interruption of a light source by an eight vane fan. The pulse rate is proportional to the fan's angular speed and linearly related to wind velocity over the range 0.25 to 4.27 m/sec.
Carpini, T. D.↗
Anemometers STRATCOM 8-A
The wind anemometer is based on the use of bead thermistors exposed to the air flow and operated in a constant temperature mode. Matched thermistor pairs operating at different temperatures are used to eliminate the dependence on ambient temperature and pressure. Air density dependence is accounted for by the use of an enclosed reference pair of thermistors. At pressures lower than 10 mm Hz, the reference pair may serve as densitometer. Calibration is based on the measurement of the difference in thermistor power as a function of Reynolds number by varying wind speed and density.
Mcdonald, C.↗
Laser Doppler anemometer diagnostics in unsteady flows
The application of the laser Doppler anemometer (LDA) to unsteady flows is discussed with respect to necessary features of the signal processor, properties of the optical system, and the character of the flow under investigation. The discussion of signal processors includes consideration of frequency trackers, counter-type processors, particle properties, data rates, and statistics. Secondly, diffraction limitations for an optical system are viewed with respect to spatial resolution. Finally, the total velocity field is decomposed into its subfields and the feasibility of, criteria for, and possible types of conditional sampling are defined. Several reported LDA experiments using conditional sampling are presented to demonstrate the different techniques that may be used.
Orloff, K. L.↗
Split-film anemometer measurements on an airfoil with turbulent separated flow
Experimental studies of turbulent separation on airfoils have been conducted to aid in improving theoretical models of post-stall airfoil behavior. The studies utilize a variety of pressure and hot-film probes. The split-film anemometer has proved particularly valuable for measurement of highly turbulent reversing flows. Suggested techniques for on-line digital computer processing of the data are discussed.
Wentz, W. H., Jr.↗
Particle size and velocity measurement in flames by laser anemometer
Simultaneous droplet size and velocity measurements by a particle counting Laser Doppler Anemometer (LDA) in kerosene fuel sprays under burning and non-burning conditions are presented. Particle sizes are derived from pulse height analysis of the mean LDA signals and velocities are simultaneously determined by measuring Doppler shift frequencies. The measurements show that droplet velocity is a function of droplet diameter for burning and non-burning conditions, and spatially averaged size distributions are derived from velocity data. A comparison of results obtained under burning and non-burning conditions show changes in size distribution due to preferential vaporization of small droplets, acceleration due to thermal expansion of gases, and corresponding changes in droplet momentum.
Chigier, N. A.↗