by Gas Dynamics Division, The University of Tennessee Space Institute, National Aeronautics and Space Administration, National Technical Information Service, distributor in Tullahoma, TN, [Washington, DC, Springfield, Va .
Written in English
|Statement||by A.D. Vakili, J.M. Wu|
|Series||NASA contractor report -- NASA CR-176818|
|Contributions||Wu, Cheng-ming, 1945-, United States. National Aeronautics and Space Administration|
|The Physical Object|
In hypervelocity, the skin friction is proportional to the product of the gas density multiplied by the square of the flight velocity. Related research results  show that the skin friction drag accounts for almost 50 % of the total drag in hypersonic vehicles with : Lv Zhiguo, Lv Zhiguo, Li Guojun, Zhao Rongjuan, Jiang Hua, Liu Jichun, Huang Jun, Liu Shiran. The principal objective of this technology development program was to design, build, and test a new class of direct-measuring skin friction sensors capable of performing favorably under a standard hypersonic flow test program at AEDC Hypervelocity Wind Tunnel 9, located at White Oak, Maryland. Fully understanding and optimizing these complex flows requires knowledge of the Author: Ryan J. Meritt, Joseph A. Schetz, Eric C. Marineau, Daniel R. Lewis, Derick T. Daniel. The instrument has three major parts: casing, pressure cell, and cantilever. The casing protects the pressure cell which measures lateral earth pressure. Strain gages on the cantilever, which screws into the back of the casing, measure skin friction. The instrument has been tested by embedding it in a precast concrete pile driven in natural by: 3. Joseph A. Schetz. A new type of direct-measuring skin-friction gauge was developed for the high-speed, high-temperature environment of turbulent boundary-layer flows in supersonic combustion.
The feasibility of measuring the skin friction from the movement of interference fringes of a thin oil ﬁlm was ﬁrst realized by Tanner and Blows (). Oil-ﬁlm interferometry is the only direct method for skin-friction measurement apart from ﬂoating-element balances. It has a high spatial resolution and is capable of measuring reverse. Direct measurement of the skin friction with a skin friction drag balance, under the same aerodynamic conditions, lets us correlate the skin friction with optical transmission. This provides a unique technique for the direct measurement of skin friction from the transmitted light intensity. The results are in excellent agreement with the model. The first part is an introduction to skin friction and to current knowledge on skin friction. The second part presents the RevoltST, the tribometer that was specially developed for skin friction research and which meets the objectives described in the thesis. The third part presents the results of the skin friction measurements obtained with. A study was conducted on the measurement of skin friction, the least under-stood component of drag. Skin friction is considered the “last frontier” in drag reduc-tion for supersonic flight, but to understand skin friction, it must be accurately mea s-ured. This study utilized the direct measuring technique for skin friction. A small de-.
An emerging area of application for skin friction measurements is as critical and sensitive inputs for flow control systems. Since skin friction (or wall shear) measurement is an important topic, there is a long history of work in the area starting with Froude (). There are two broad classes of methods – indirect and direct measurements. Skin friction and oil-film development. Quantitative skin friction measurements were made by using image-based interferometry for determining the thickness of an oil drop on a surface. Data processing in interferometric oil-film skin friction meter is based on a local similarity solution of the thin-oil-film equation providing. A device has been developed to measure local skin friction on a flat plate by measuring the force exerted upon a very small movable part of the surface of a flat plate. These forces, which range from about 1 milligram to about milligrams, are measured by means of a reluctance measuring device. The apparatus was first applied to measurements in the low-speed range, both for laminar and. A simple instrument for skin-friction measurements in adiabatic turbulent compressible boundary-layers is described. Its small size makes its use possible in very thin boundary layers. A universal calibration relation is given.