Experimental Study of Error Sources in Skin-Friction Balance Measurements

Allen, Jerry M.

doi:10.1115/1.3448523

Cited by 40 publications

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“…Tennant and McAllister (1980), Brown and Joubert (1969), Smith and Walker (1958), Vinh (1973), Allen (1977), Fowke (1969), Everett (1958), Boyce and r' Blick (1971), Boyce and Blick (1969), Waltrup (1971), Miller (1972; 1 in anuular shapes by Franklin (1961), White and Franklin (1964), Smith, Lawn and Hamlin (1968), on a cylinder by Horsey (1974), and on flat plates by Depooter, Brundrett and Strong (1977), Hakkinen (1955), Dhawan (1952) Smith and Walker (1958), the NFL Staff (1958), Rechenberg (1963), Ferriss (1965), Head and Rechenberg (1962), Patel (1965), Brown and Joubert (1969), Miller (1972), and-Samuel and Joubert (1974; Stanton tubes used by Stanton, Marshall and Bryant (1920), Konstantinov and Dragnysh (1960), and Bradshaw and Gregory (1961); sublayer fences used by Wills (1963), , Wanschkuhn and Vasanta Ram (1975); razor blades used by East (1968), Wyatt and East (1968), Pai and Whitelaw (1969) Tennant (1977) and McAllister (1979). …”

Section: =mentioning

confidence: 99%

Near-Wall Similarity in a Pressure-Driven Three-Dimensional Turbulent Boundary Layer

Pierce

McAllister

1983

Journal of Fluids Engineering

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Interim 14. IX Supplementary Notes_16. "Exte n sive measurements of the mean velocity, wall pressure and wall shear stress fields were Meade in a three-dimensional pressure-driven turbulent boundary layer created by a cylinder with trailing edge placed normal to a flat plate floor.The direct force wall shear stress measurements were made with a unique, floating element direct force sensing shear mater that responded to both the magnitude and direction of the local wall shear stress.These data were used to test the ability of ten near-wall similarity models proposed in the literature to describe the near-wall velocity field for the measured flow under a wiee range of skewing conditions and a variety of pressure gradient and wall shear vector orientations. S. Performing Organization Report Number. Insect if perfotming organization wishes to assign this number.9. Performing Organization Name and Mailing Address. Give name, street, city, state, and zip code. List no more than two levels of an organizational hierarchy. Display the name of the organization exactly as it should appear in Government indexes such as Government Reports Index (GRI).10. Project/ Took/Work Unit Number. Use the project, task and work unit numbers under which the report was prepared.11. Contract/Grant Number. Insert contract or grant number under which report was prepared.12. Sponsoring Agency Name and Mailing Address. Include zip code. C:-e main sponsors.13. Since the majority of documents are multidisciplinary in nature, the primary Field/Group assignment(s) will be the specific discipline, area of human endeavor, or type of physical object. The application(s) will be cross-referenced with secondary Field/Group assignments that will follow the primary posting(s).18. Distribution Statement. Denote public relessabilicy, for example " Release unlimited", or limitation for reasons other than security. Cite any availability to the public, other than NTIS, with address, order number and price, if known. These three-dimensional velocity field, wall pressure field, and wall shear field results were used to test the ability of ten near-wall similarity models proposed in the literature for three-dimensional turbulent boundary layers to describe the near-wall velocity field. Six of these ten models are scalar, treating some form of an equivalent velocity component. Three of the remaining four more complex models are twocomponent vector models and the last is a scalar model which recognizes the vector nature of the near-wall flow by way of a developed velocity.All. of the ten models tested find their origin, directly or indirectly, in an equilibrium boundary layer hy pothesis using a mixing length. there is the problem of fixing a lower y + limit below which data could not be used.If one were to use these three more complex models in a computational scheme replacing the no slip wall boundary condition at the wall with a match to a similarity model near the wall, then for the flows described above, such a match should be made in a range of about 50 < y ...

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Section: =mentioning

confidence: 99%

Near-Wall Similarity in a Pressure-Driven Three-Dimensional Turbulent Boundary Layer

Pierce

McAllister

1983

Journal of Fluids Engineering

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“…The deflection of the beam can be measured by using strain gages or optical methods. The presence of this gap and the deflection of the floating head can lead to increased uncertainties in the results due to slight interference with the flow, as shown by Allen [22]. Many variations of this type of sensor exist, including sensors with filler in the gap, a rubber sheet across the top surface covering the beam and gap, or sensors utilizing a bellows to isolate the strain gages for use in hot-flow environments.…”

Section: Direct Methodsmentioning

confidence: 99%

Design, Analysis, and Testing of Nanoparticle-Infused Thin Film Sensors for Low Skin Friction Applications

Leslie¹,

Schetz²,

Hill³

2013

AIAA Ground Testing Conference

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Accurate measurement of skin friction in complex flows is important for: documentation and monitoring of fluid system performance, input information for flow control, development of turbulence models and CFD validation. The goal of this study was to explore using new materials to directly measure skin friction in a more convenient way than available devices. Conventional direct measurement skin friction sensors currently in use are intrusive, requiring movable surface elements with gaps surrounding that surface, or require optical access for measurements. Conventional direct measurement sensors are also difficult to apply in low shear environments, in the 1-10 Pa range. A new thin, flexible, nanoparticle infused, piezoresistive material called Metal Rubber TM was used to create sensors that can be applied to any surface. This was accomplished by using modern computerized finite element model multiphysics simulations of the material response to surface shear loads, in order to design a sensor configuration with a reduced footprint, minimal cross influence and increased sensitivity. These sensors were then built, calibrated in a fully-developed water channel flow and tested in both the NASA 20x28 inch Shear Flow Control Tunnel and a backwards facing step water flow. The results from these tests showed accurate responses, with no amplification to the sensor output, to shear levels in the range of 1-15 Pa. In addition, the computer model of these sensors was found to be useful for studying and developing refined sensor designs and for documenting sources of measurement uncertainty. These encouraging results demonstrate the potential of this material for skin friction sensor applications.iii Acknowledgements I would like to thank everyone who has contributed to the success of this project. Without the help of each individual, some piece of this project may not have come to fruition. -To my friends and family: I could not have made it this far without your love and continued support.-Dr. Joseph Schetz, my advisor, it has been wonderful studying under you. Your vast knowledge, experience, critical thinking, and leadership has inspired me throughout my education here at Virginia Tech and will continue to inspire me to excel in my professional life. Your guidance and support, including providing me with housing when I was without, has helped me to overcome numerous obstacles over the course of this project.-The members of my advisory committee, Dr. Rick Claus, Dr. Micheal Philen, and Dr. Gary Seidel who have provided assistance and advice over the course of this research. I appreciate all of the time you given to help me in my education and in this research.-The many other professors at Virginia Tech who have given time to help sort out issues or to better understand a topic. Specifically I would like to thank Dr. Todd Lowe for his significant effort in getting LDV measurements in the Water Channel. I would also like to thank Dr. Roger Simpson for help with studying turbulence, Dr. Christopher Roy for his assistance with...

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“…It has long been known that the floating head geometry is important to a successful direct measuring skin friction gage, leading to several studies of the effects of floating head geometry on measurement uncertainties 33,34 . Some of the more notable work was done by Allen 19,20 in the 1970's. He identified important floating head geometric parameters and studied their effects, including the effects of misalignment of the floating head, on the error in direct skin friction measurements.…”

Section: Floating Head Design Attributes and Concernsmentioning

confidence: 99%

“…A schematic of his device is shown above in Figure 5. The work that followed, including that of Allen 19,20 , Voisinet 21 , and Roensch and Cadwell…”

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Development and Ground Testing of Direct Measuring Skin Friction Gages for High Enthalpy Supersonic Flight Tests

Smith

2002

22nd AIAA Aerodynamic Measurement Technology and Ground Testing Conference

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Aerospace Engineering (ABSTRACT)A series of direct-measuring skin friction gages were developed for a high-speed, high-temperature environment of the turbulent boundary layer in flows such as that in supersonic combustion ramjet (scramjet) engines, with a progression from free-jet ground tests to a design for an actual hypersonic scramjet-integrated flight vehicle. The designs were non-nulling, with a sensing head that was flush with the model wall and surrounded by a small gap. Thus, the shear force due to the flow along the wall deflects the head, inducing a measurable strain. Strain gages were used to detect the strain. The gages were statically calibrated using a direct force method. The designs were verified by testing in a well-documented Mach 2.4 cold flow. Results of the cold-flow tests were repeatable and within 15% of the value of C f estimated from simple theory. The first gage design incorporated a cantilever beam with semiconductor strain gages to sense the shear on the floating head. Cooling water was routed both internally and around the external housing in order to control the temperature of the strain gages. This first gage was installed and tested in a rocket-based-combined-cycle (RBCC) engine model operating in the scramjet mode. The free-jet facility provided a Mach 6.4 flow with P 0 = 1350 psia (9310 kPa) and T 0 = 2800 °R (1555 °K). Local wall temperatures were measured between 850 and 900 °R (472-500 °K). Output from the RBCC scramjet tests was reasonable and repeatable. A second skin friction gage was designed for and tested in a wind tunnel model of the Hyper-X flight vehicle scramjet engine. These unsuccessful tests revealed the need for a radically different skin friction gage design.The third and final skin friction gage was specifically developed to be installed on the Hyper-X flight vehicle. Rather than the cantilever beam and semiconductor strain gages, the third skin friction gage made use of a flexure ring and metal foil strain gages to sense iii the shear. The water-cooling and oil-fill used on the previous skin friction sensors were eliminated. It was qualified for flight through a rigorous series of environmental tests, including pressure, temperature, vibration, and heat flux tests. Finally, the third skin friction gage was tested in the Hyper-X Engine Model (HXEM), a full-scale-partial-width wind tunnel model of the flight vehicle engine. These tests were conducted at Mach 6.5 enthalpy with P 0 = 555 psia (3827 kPa) and h 0 = 900 Btu/lb m in a freejet facility. The successful testing in the wind tunnel scramjet model provided the final verification of the gage before installation in the flight vehicle engine. The development, testing, and results of all three skin friction gages are discussed.

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Experimental Study of Error Sources in Skin-Friction Balance Measurements

Cited by 40 publications

References 0 publications

Near-Wall Similarity in a Pressure-Driven Three-Dimensional Turbulent Boundary Layer

Near-Wall Similarity in a Pressure-Driven Three-Dimensional Turbulent Boundary Layer

Design, Analysis, and Testing of Nanoparticle-Infused Thin Film Sensors for Low Skin Friction Applications

Development and Ground Testing of Direct Measuring Skin Friction Gages for High Enthalpy Supersonic Flight Tests

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