The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
G. M. Frees - One of the best experts on this subject based on the ideXlab platform.
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Tracking Dynamics of Read/Write Head Suspensions in High-Performance Small Form Factor Rigid Disk Drives
Journal of Vibration and Acoustics, 1990Co-Authors: G. M. Frees, R. S. GompertzAbstract:Recording density of rigid disk drives is related to both linear and track density. High linear density requires submicron recording spacing which is made possible by using a gas-lubricated slider bearing to support the read/write transducer. This critical component has inspired much reseach effort in the past, both in industry and in academia. On the other hand, a major limitation in increasing the track density is the structural resonance of the suspension which connects the slider bearing to the actuator arm. In this paper, a Nonintrusive Measurement Technique using a Laser Doppler Vibrometer is utilized to measure the submicron suspension vibration
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Experimental and Numerical Analysis of Read/Write Head Suspension Dynamics for High-Performance Floppy Drive Systems
Journal of Vibration and Acoustics, 1990Co-Authors: G. M. FreesAbstract:Read/write head suspensions are critical components of high-performance floppy disk drives. Their dynamics affect head/media compliance, wear, and tracking performance. Vibration Measurements are necessary in order to verify and adjust finite element models, to observe the influence of actual loading and operating conditions, and to study the effects of unmodeled components such as electrical wires and adhesives. A Nonintrusive Measurement Technique using a Laser Doppler Vibrometer is utilized to measure the submicron vibrations. Excitation of the suspension is provided by a specially designed miniature air hammer and a piezoelectric transducer. Natural frequencies and mode shapes are extracted from the Measurements and compared with numerical data from the finite element model. Research shows that boundary conditions are the most important parameters in the modeling of the suspension. A new design is proposed, using the verified model, to increase the tracking performance of the suspension. Synergy between experimentation and numerical analysis is emphasized.
R. S. Gompertz - One of the best experts on this subject based on the ideXlab platform.
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Tracking Dynamics of Read/Write Head Suspensions in High-Performance Small Form Factor Rigid Disk Drives
Journal of Vibration and Acoustics, 1990Co-Authors: G. M. Frees, R. S. GompertzAbstract:Recording density of rigid disk drives is related to both linear and track density. High linear density requires submicron recording spacing which is made possible by using a gas-lubricated slider bearing to support the read/write transducer. This critical component has inspired much reseach effort in the past, both in industry and in academia. On the other hand, a major limitation in increasing the track density is the structural resonance of the suspension which connects the slider bearing to the actuator arm. In this paper, a Nonintrusive Measurement Technique using a Laser Doppler Vibrometer is utilized to measure the submicron suspension vibration
Charles Tyler - One of the best experts on this subject based on the ideXlab platform.
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Analysis of a Rayleigh scattering Measurement system in a hypersonic wind tunnel
35th Aerospace Sciences Meeting and Exhibit, 1997Co-Authors: Charles Tyler, Franklin E. EastepAbstract:Rayleigh scattering, a Nonintrusive Measurement Technique for the Measurement of density in a hypersonic wind tunnel, has been under investigation at Wright Laboratory's Mach 6 wind tunnel. Several adverse effects, e.g. extraneous scatter off tunnel surfaces and condensation of flow constituents, hinder efforts to obtain accurate Rayleigh scattering Measurements. Overcoming some of these difficulties, Measurements have been achieved while the Mach 6 test section was pumped to a vacuum, as well as for actual tunnel operation for various stagnation pressures at fixed stagnation temperatures. Stagnation pressures ranged from 0.69MPa to 6.9MPa at fixed stagnation temperatures of 511, 556, and 61 IK. Rayleigh scatter results show signal levels much higherthan-expected for molecular scattering in the wind tunnel. Even with higher-than-expected signals, scatter Measurements have been made in the flowfield of a 8degree half-angle blunt nose cone with a nose radius of 1.5cm.
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Laser velocimetry in the supersonic regime: Advancements, limitations, and outlook
SAE Technical Paper Series, 1993Co-Authors: Mark S. Maurice, Charles Tyler, Linda G. Smith, George L. Seibert, C. Dean MillerAbstract:Laser Velocimetry (LV) is often utilized as an off-the-shelf Nonintrusive Measurement Technique for low speed, steady state flows. However, in complex, supersonic flows, the application of LV becomes highly specialized. Set-ups must often contend with limited optical access, poor signal-to-noise ratios, and limited tunnel run times. Furthermore, seeding particles must survive large ranges of flow temperatures and pressures, and extensive data analysis and interpretation are required to ascertain whether measured particle velocities are representative of the fluid flow. Several examples of LV studies in the supersonic regime demonstrate recent advancements and the current state-of-the-art of this Measurement Technique. Results are included from three wind tunnel facilities, operating at freestream Mach numbers of 1.9, 3, and 6, and track an evolution of applications from flat plate boundary layers to the complex flowfield of a supersonic inlet. Results demonstrate that further development of collection, seeding and analysis Techniques will continue to extend the range of LV applications and Measurement statistics, but the overall limiting factor will continue to be the ability of LV seed to model the discrete motion of fluid molecules.
Bai Junqiang - One of the best experts on this subject based on the ideXlab platform.
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a high speed nature laminar flow airfoil and its experimental study in wind tunnel with Nonintrusive Measurement Technique
Chinese Journal of Aeronautics, 2009Co-Authors: Gao Zhenghong, Bai JunqiangAbstract:Abstract This article deals with an experimental study on the aerodynamic characteristics of a low-drag high-speed nature laminar flow (NLF) airfoil for business airplanes in the TST27 wind tunnel at Delft University of Technology, the Netherlands. In this experiment, in an attempt to reduce the errors of Measurement and improve its accuracy in high-speed flight, some Nonintrusive Measurement Techniques, such as the quantitative infrared thermography (IRT), the digital particle imaging velocimetry (PIV), and the shadowgraphy, are applied to obtain precise data about transition locations, separation on trailing edges, and lift/drag characteristics. The experimental results reveal that, in the high-speed flight, small angles of attack are helpful in retaining long laminar flows, preventing the vortex at the trailing edge from moving forward and thus imparting the airfoil and the high-lift and low-drag characteristics. The comparison of the measured results to the calculated ones proves the acceptability of the airfoil and its aerodynamic characteristics satisfying the design requirements.
Franklin E. Eastep - One of the best experts on this subject based on the ideXlab platform.
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Analysis of a Rayleigh scattering Measurement system in a hypersonic wind tunnel
35th Aerospace Sciences Meeting and Exhibit, 1997Co-Authors: Charles Tyler, Franklin E. EastepAbstract:Rayleigh scattering, a Nonintrusive Measurement Technique for the Measurement of density in a hypersonic wind tunnel, has been under investigation at Wright Laboratory's Mach 6 wind tunnel. Several adverse effects, e.g. extraneous scatter off tunnel surfaces and condensation of flow constituents, hinder efforts to obtain accurate Rayleigh scattering Measurements. Overcoming some of these difficulties, Measurements have been achieved while the Mach 6 test section was pumped to a vacuum, as well as for actual tunnel operation for various stagnation pressures at fixed stagnation temperatures. Stagnation pressures ranged from 0.69MPa to 6.9MPa at fixed stagnation temperatures of 511, 556, and 61 IK. Rayleigh scatter results show signal levels much higherthan-expected for molecular scattering in the wind tunnel. Even with higher-than-expected signals, scatter Measurements have been made in the flowfield of a 8degree half-angle blunt nose cone with a nose radius of 1.5cm.
