Installation of a rectangular test section for acoustic water tunnel studies of flow‐induced noise

This paper reports on the characterization of the custom-designed high-Reynolds number recirculating water tunnel located at Oklahoma State University. The characterization includes the verification of the test section design, pump calibration and the velocity distribution within the test section. This includes an assessment of the boundary layer growth within the test section. The tunnel was designed to achieve a downstream distance based Reynolds number of 10 million, provide optical access for flow visualization and minimize inlet flow non-uniformity. The test section is 1 m long with 15.2 cm (6-inch) square cross section and acrylic walls to allow direct line of sight at the tunnel walls. The verification of the test section design was accomplished by comparing the flow quality at different location downstream of the flow inlet. The pump was calibrated with the freestream velocity with three pump frequencies and velocity profiles were measured at defined locations for three pump speeds. Boundary layer thicknesses were measured from velocity profile results and compared with analytical calculations. These measurements were also compared against the facility design calculations.

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SDSU Water Tunnel Test Section Flow Quality Characterization

AIAA Scitech 2020 Forum ◽

10.2514/6.2020-0030 ◽

2020 ◽

Author(s):

Jose R. Moreto ◽

Xiaofeng Liu

Keyword(s):

Test Section ◽

Water Tunnel ◽

Flow Quality

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CFD Simulation and Experimental Validation of a New Closed Circuit Wind/Water Tunnel Design

Journal of Fluids Engineering ◽

10.1115/1.2820650 ◽

1998 ◽

Vol 120 (2) ◽

pp. 311-318 ◽

Cited By ~ 12

Author(s):

Robert Gordon ◽

Mohammed S. Imbabi

Keyword(s):

Test Section ◽

Cfd Simulation ◽

Decisive Role ◽

Cost Effective ◽

Closed Circuit ◽

Working Fluid ◽

Water Tunnel ◽

Measured Velocity ◽

Tunnel Design ◽

Set Up

A new closed-circuit wind/water tunnel to support flow visualization research was designed and constructed at The University of Aberdeen. Review of existing closed-circuit tunnel designs revealed that they are large, expensive, difficult to set up and maintain, and typically employ a single working fluid. Key objectives of the work reported here were to reduce the overall cost and size of the tunnel, facilitate the use of alternative working fluids (air or water), and provide high quality flow within the test section. Conventional design methods were used initially, and computational fluid dynamics (CFD) was then employed to simulate the flow within critical sections of the tunnel. The results from CFD played a decisive role in identifying the modifications needed to achieve the compact, cost-effective tunnel design eventually built and tested. Flow quality within the test section was established using measured velocity profiles, and these are also presented.

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Hydrodynamic Performance of the Large Cavitation Channel (LCC)

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45599 ◽

2003 ◽

Cited By ~ 3

Author(s):

Joel T. Park ◽

J. Michael Cutbirth ◽

Wesley H. Brewer

Keyword(s):

Test Section ◽

Single Point ◽

Temporal Stability ◽

Hydrodynamic Performance ◽

Water Tunnel ◽

Axial Velocity Component ◽

Pump Speed ◽

Additional Information ◽

Spatial Uniformity ◽

Contour Plots

The U. S. Navy William B. Morgan Large Cavitation Channel (LCC) in Memphis, Tennessee, is the world’s largest water tunnel. Its hydrodynamic performance is outlined in this paper. Three key characteristics of tunnel velocity were measured: temporal stability, spatial uniformity, and turbulence. Temporal stability and spatial uniformity were measured by laser Doppler anemometer (LDA), while the turbulence was measured with a conical hot-film and constant temperature anemometer (CTA). The velocity stability at a single point for run times greater than 2 hours was measured as ±0.15% at the 95% confidence level for velocities from 0.5 to 18 m/s. The spatial non-uniformity for the axial velocity component was ±0.34 to ±0.60% for velocities from 3 to 16 m/s. The non-uniformity in the vertical velocity was nominally 2%. The turbulence or relative turbulence intensity, which is the commonly reported performance characteristic for water tunnels, was measured as 0.2 to 0.5% depending on tunnel velocity. Additional information includes calibration of the LDA and CTA, test section velocity as a function of pump speed, acceleration of the test section velocity, velocity spectra, and color contour plots of the axial and vertical components for velocity uniformity. The measurements demonstrate that the LCC is a high-quality world-class water tunnel.

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Design and Validation of a Recirculating, High-Reynolds Number Water Tunnel

Journal of Fluids Engineering ◽

10.1115/1.4039509 ◽

2018 ◽

Vol 140 (8) ◽

Cited By ~ 5

Author(s):

Brian R. Elbing ◽

Libin Daniel ◽

Yasaman Farsiani ◽

Christopher E. Petrin

Keyword(s):

Boundary Layer ◽

Reynolds Number ◽

Test Section ◽

High Reynolds Number ◽

Water Tunnel ◽

Laminar To Turbulent Transition ◽

Turbulent Transition ◽

Profile Matching ◽

Final Design ◽

High Reynolds

Commercial water tunnels typically generate a momentum thickness based Reynolds number (Reθ) ∼1000, which is slightly above the laminar to turbulent transition. The current work compiles the literature on the design of high-Reynolds number facilities and uses it to design a high-Reynolds number recirculating water tunnel that spans the range between commercial water tunnels and the largest in the world. The final design has a 1.1 m long test-section with a 152 mm square cross section that can reach speed of 10 m/s, which corresponds to Reθ=15,000. Flow conditioning via a tandem configuration of honeycombs and settling-chambers combined with an 8.5:1 area contraction resulted in an average test-section inlet turbulence level <0.3% and negligible mean shear in the test-section core. The developing boundary layer on the test-section walls conform to a canonical zero-pressure-gradient (ZPG) flat-plate turbulent boundary layer (TBL) with the outer variable scaled profile matching a 1/7th power-law fit, inner variable scaled velocity profiles matching the log-law and a shape factor of 1.3.

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An Acoustic Procedure for Measuring Blade-Frequency Forces Generated by Model Ship Propellers

10.1115/imece2001/nca-23500 ◽

2001 ◽

Author(s):

M. Strasberg

Keyword(s):

Wind Speed ◽

Wind Tunnel ◽

Test Section ◽

Sound Pressure ◽

Water Tunnel ◽

Measurement Point ◽

Theoretical Relation ◽

Point Measurement ◽

Direct Measurements ◽

Blade Frequency

Abstract An acoustic procedure is described for measuring the blade-frequency fluctuating forces developed by a powered model propeller operating behind a model of a ship’s hull or a wake generator in the anechoic test section of a wind tunnel. The sound pressure radiated by the propeller in a given direction is measured and its magnitude inserted into a simple theoretical relation to determine the alternating force developed by the propeller in that direction. Although the procedure was developed years ago, the details and limitations have not previously been described in the literature. Restrictions are discussed on the size of the propeller, location of the measurement point, measurement frequency, and the wind speed. Measurements determining the validity of the procedure are described, including comparisons of the magnitude of forces determined by this acoustic procedure with direct measurements made with a force dynamometer in a water tunnel.

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PIV investigation of cavitating flows around circular cylinders with hydrophobic coatings

14th International Symposium on Particle Image Velocimetry ◽

10.18409/ispiv.v1i1.101 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Konstantin Dobroselsky ◽

Anatoliy Lebedev ◽

Alexey Safonov ◽

Sergey Starinskiy ◽

Vladimir Dulin

Keyword(s):

Test Section ◽

Pressure Sensors ◽

Circular Cylinders ◽

Bulk Velocity ◽

Water Tunnel ◽

Slip Effect ◽

Long Distance ◽

Hydrophobic Coatings ◽

Heating Section ◽

Near Wall

The treatment of the hydrophobic properties of solid surfaces is considered as a passive method to reduce the drag in water flows (Rothstein, 2010) and to potentially affect the flow separation and vortex shedding (Sooraj et al., 2020). The manufacturing of surfaces with micro- and nano-scale roughness allows to extend the hydrophobicity towards superhydrophobicity with the contact angle close to 180°. In such conditions the solid surface is not wetted completely and the air-water interphase partially remains on the surface texture. This results in so-called flow slip effect. Therefore, a local phase transition during the flow cavitation or gas effervescence in near-wall low-pressure regions may additionally affect the slip effect for hydrophobic surfaces. The present work is focused on the comparison between cavitating and noncavitating flows around circular cylinders with lateral sectors with hydrophobic and non-hydrophobic coatings. The experiments are performed in a water tunnel, which consists of a water outgassing and cooling/heating section, honeycomb, contraction section, test section and diffuser. The water flow is driven by an electric pump, providing a bulk velocity up to 10 m/s in the transparent test section with 1 m length and 80×150 mm2 rectangular cross-section. The facility is equipped with an ultrasonic flowmeter, temperature and pressure sensors. Besides, the static pressure inside the water tunnel can be varied by using a special shaft section. The measurements are performed by using high-repetition and low-repetition PIV systems. The former is used for the analysis of large-scale flow dynamics in the wake region, whereas the latter one is used for high-resolution measurements in near-wall regions by using a long-distance microscope. The Reynolds number based on the bulk velocity of the flow, diameter of the cylinders (D = 26 mm) and kinematic viscosity of the water is varied up to 2×105..

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