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Institution

Naval Surface Warfare Center

FacilityWashington D.C., District of Columbia, United States
About: Naval Surface Warfare Center is a facility organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Sonar & Radar. The organization has 2855 authors who have published 3697 publications receiving 83518 citations. The organization is also known as: NSWC.


Papers
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Proceedings ArticleDOI
TL;DR: In this paper, the authors examined the film cooling performance on the pressure side of a turbine vane subjected to high mainstream turbulence levels, with and without showerhead blowing, and found that the large scale high-mainstream turbulence causes a lateral oscillation of the coolant jet resulting in a much wider time average distribution of coolant.
Abstract: This study focused on the film cooling performance on the pressure side of a turbine vane subjected to high mainstream turbulence levels, with and without showerhead blowing. Whereas previous studies have measured the adiabatic effectiveness and heat transfer at the surface of the airfoil, the goal of this study was to examine the flow and thermal fields above the surface. These measurements included flow visualization, thermal profiles, and laser Doppler velocimetry. For comparison, adiabatic effectiveness was also measured. A mainstream turbulence level of Tu∞ = 20%, with integral length scale of seven hole diameters, was used. Particularly insightful is the discovery that the large scale high mainstream turbulence causes a lateral oscillation of coolant jet resulting in a much wider time average distribution of coolant. Even with high mainstream turbulence, showerhead blowing was found to still cause a significantly increased dispersion of the pressure side coolant jets.Copyright © 2002 by ASME

17 citations

Journal ArticleDOI
TL;DR: In this paper, the impact induced slamming loads experienced by ships and offshore structures using advanced fluid structure interaction methods may be a challenging task involving complex and time consuming engineering solutions, which is the reason why the application of well understood and validated quasi-response approaches remains the most rational alternative used by experts for preliminary design assessment.

17 citations

Proceedings ArticleDOI
29 Jun 1994
TL;DR: In this paper, two different methods for obtaining suboptimal smoothed estimates are given, where the methods differ by the sampling period upon which the state of the system is conditioned.
Abstract: Suboptimal approaches to the one-step fixed-lag smoothing problem for Markovian switching systems are examined in this paper. Two different methods for obtaining suboptimal smoothed estimates are given, where the methods differ by the sampling period upon which the state of the system is conditioned. For n models, the first method requires n/sup 2/ predictions and residual evaluations, while the second method requires n residual evaluations. Simulation results are presented to compare the performances of the two smoothers.

17 citations

Proceedings ArticleDOI
13 Jun 2005
TL;DR: In this paper, a semiconductor-device model is presented that captures device reverse- recovery and on-state conduction behavior utilizing a time-varying resistance that depends on the solid-state device properties and operating circuit parameters.
Abstract: As pulsed-power systems used to drive EM launchers evolve from laboratory to operational environments, high- power solid-state devices are emerging as the leading switch technology for these systems. These devices, specifically high-power thyristors and diodes, offer the advantages of improved energy efficiency, reduced volume, and reduced auxiliaries over spark-gaps and ignitrons. Proper application of these devices requires understanding of their behavior both during forward conduction and during reverse recovery. The semiconductor device models available in most circuit simulation software packages do not accurately characterize large power thyristors and diodes for thermal management and snubber design. A semiconductor- device model is presented that captures device reverse- recovery and on-state conduction behavior utilizing a time-varying resistance that depends on the solid-state device properties and operating circuit parameters. The information needed to construct this model can be extracted from the device datasheet or obtained from the manufacturer. This circuit model is used to analyze pulsed-power circuits typically used to drive railguns. Of key interest in these simulations are the voltage transients and energy losses in the solid-state devices during the reverse- recovery process. This behavior is analyzed for different circuit element values and device parameters such as peak reverse current, and reverse recovery charge.

17 citations

Journal ArticleDOI
TL;DR: The stress, strain, and dilatation characteristics are presented fora dislocation structure proposed by Armstrong, Miller, and Sandusky (AMS) to give a residual one-dimensional strain state.
Abstract: Dislocation structures proposed to model plastic deformation at a shock front are analyzed. The creation and glide movement of the dislocations are considered. Glide-type movement violates the condition of one-dimensional strain except if dislocation dipoles with Burgers vectors parallel and antiparallel to the shock propagation direction are directly generated by alternating shear stresses as in a punching action. The stress, strain, and dilatation characteristics are presented for a dislocation structure proposed by Armstrong, Miller, and Sandusky (AMS) to give a residual one-dimensional strain state. The AMS dislocation structure is related to independent results from a molecular-dynamics description of shear displacements in a shocked triangular lattice and is used as a basis for estimating the extent of postshock strengthening levels. The shock-strengthening predictions are in reasonable agreement with postshock deformation measurements.

17 citations


Authors

Showing all 2860 results

NameH-indexPapersCitations
James A. Yorke10144544101
Edward Ott10166944649
Sokrates T. Pantelides9480637427
J. M. D. Coey8174836364
Celso Grebogi7648822450
David N. Seidman7459523715
Mingzhou Ding6925617098
C. L. Cocke513128185
Hairong Qi503279909
Kevin J. Hemker4923110236
William L. Ditto431937991
Carey E. Priebe434048499
Clifford George412355110
Judith L. Flippen-Anderson402056110
Mortimer J. Kamlet3910812071
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20233
20227
202172
202071
201982
201884