Pressurized temperature-variable water tunnel for high Reynolds number research

2016 ◽

Cited By ~ 3

Author(s):

Yasaman Farsiani ◽

Brian R. Elbing

Keyword(s):

Boundary Layer ◽

Reynolds Number ◽

Test Section ◽

High Reynolds Number ◽

Layer Growth ◽

Water Tunnel ◽

Freestream Velocity ◽

Section Design ◽

High Reynolds

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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Design of a Recirculating Water Tunnel for the Study of High-Reynolds Number Turbulent Boundary Layers

Volume 7B: Fluids Engineering Systems and Technologies ◽

10.1115/imece2015-52030 ◽

2015 ◽

Author(s):

Libin Daniel ◽

Shahrouz Mohagheghian ◽

Dalton Dunlap ◽

Eric Ruhlmann ◽

Brian R. Elbing

Keyword(s):

Reynolds Number ◽

Boundary Layers ◽

High Reynolds Number ◽

Low Cost ◽

Turbulent Boundary Layers ◽

Regulation System ◽

Water Tunnel ◽

Overall Design ◽

Design Considerations ◽

High Reynolds

This paper reports on the design and fabrication of a high-Reynolds number recirculating water tunnel, which will be used primarily for the study of turbulent boundary layers with an emphasis on drag reduction applications. The primary design specifications were (i) achieve a momentum thickness based Reynolds number above 10,000, (ii) maximize optical access, and (iii) minimize flow non-uniformity. This paper discusses the design considerations and procedures to meet each of these design criteria as well as the manufacturing of the components, installation, and design of auxiliary systems such as the pressure regulation system. There are several recirculating water tunnels at universities that can achieve comparable Reynolds numbers, but they were either built with at least double the budget of the current project or are refurbished tunnels from other laboratories (i.e. key design considerations were already fixed). Thus, the current work offers a guide for the overall design of a low-cost, high-Reynolds number water tunnel. A brief review of other recirculating high-Reynolds number water tunnels is included. Currently, installation has begun with the fabrication complete.

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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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