Scavuzzo R.J.,Hi-Test Laboratories, Inc |
Journal of Pressure Vessel Technology, Transactions of the ASME | Year: 2015
Often when a pipe is subjected to a shock input in the vertical direction, the pipe will vibrate horizontally after initially vibrating vertically. This vibration is beating that occurs between the vertical and horizontal modes of the pipe. Beating vibration was examined analytically by considering the principal directions of the moment of inertia of the pipe with respect to the shock input direction and by varying the support direction and stiffness at each end of a pipe. Both the moment of inertia and piping supports can produce beating. The conditions needed to initiate this phenomenon are examined and results presented. Two pipe configurations are examined: a cantilever pipe and a pipe supported at each end. In both cases, the effects of varying the principal directions of the moment inertia were examined. The end conditions were varied in the supported pipe. In one case, similar vertical and horizontal supports were specified and in the second two cases vertical supports with two different stiffnesses were analyzed. Beating was found when the end supports were in different directions. Copyright © 2015 by ASME.
News Article | November 10, 2016
Chesapeake, VA, November 10, 2016 --( Being the leader in Federal Cyber Security Solutions, Watershed Security is excited to be part of NAVSEA Carderock’s solution for Risk Management Framework (RMF) and Department of Defense (DoD) Information Assurance Certification and Accreditation (C&A) Process (DIACAP) support to the fleet. Under the DoD RMF, their industry experts will be providing Assessment & Authorization (A&A) services to NSWCDD to ensure that the security posture of NSWCDD’s systems are in full compliance with DoD, Navy, and NIST standards. Watershed will review all of the NSWCDD’s C&A and A&A artifacts to ensure that all IT systems and services will provide data integrity and that the security posture of the command is at the highest levels. “We’re very excited to be afforded an opportunity to work with NSWCDD. We have done outstanding work at other warfare centers, and we expect to deliver the same high-quality services to NSWCDD under the VRSS effort. Watershed’s Cyber Security Services are the right solution to the Navy’s accreditation challenges. Our standard approach to A&A / C&A will ensure that the Navy’s systems and infrastructure are secured at the highest levels,” said Will Swann, Director of Operations of Watershed Security. Watershed’s Chief Executive Officer (CEO), Ron Boustedt stated, “We are the lowest-risk Federal Cyber Solutions Provider, and we are looking forward to providing Watershed Security’s Cyber Solutions to the NSWCDD. We have over 14 years of experience providing C&A, DIACAP, RMF, Validation Services, and Cyber Security engineering solutions to the Federal Government. Given our solutions and experts coupled with our commitment to quality and integrity, NSWCDD will be well served by our capabilities.” For additional information please contact: Ron Boustedt at Info@WatershedSecurity.com. Chesapeake, VA, November 10, 2016 --( PR.com )-- Watershed Security, LLC, a Veteran Owned and Small Disadvantaged Business (SDB)/(8a) announced it has been awarded a two-year support services contract from NAVSEA, Carderock Division (NSWCCD) for Validation Review Support Services (VRSS).Being the leader in Federal Cyber Security Solutions, Watershed Security is excited to be part of NAVSEA Carderock’s solution for Risk Management Framework (RMF) and Department of Defense (DoD) Information Assurance Certification and Accreditation (C&A) Process (DIACAP) support to the fleet. Under the DoD RMF, their industry experts will be providing Assessment & Authorization (A&A) services to NSWCDD to ensure that the security posture of NSWCDD’s systems are in full compliance with DoD, Navy, and NIST standards. Watershed will review all of the NSWCDD’s C&A and A&A artifacts to ensure that all IT systems and services will provide data integrity and that the security posture of the command is at the highest levels.“We’re very excited to be afforded an opportunity to work with NSWCDD. We have done outstanding work at other warfare centers, and we expect to deliver the same high-quality services to NSWCDD under the VRSS effort. Watershed’s Cyber Security Services are the right solution to the Navy’s accreditation challenges. Our standard approach to A&A / C&A will ensure that the Navy’s systems and infrastructure are secured at the highest levels,” said Will Swann, Director of Operations of Watershed Security.Watershed’s Chief Executive Officer (CEO), Ron Boustedt stated, “We are the lowest-risk Federal Cyber Solutions Provider, and we are looking forward to providing Watershed Security’s Cyber Solutions to the NSWCDD. We have over 14 years of experience providing C&A, DIACAP, RMF, Validation Services, and Cyber Security engineering solutions to the Federal Government. Given our solutions and experts coupled with our commitment to quality and integrity, NSWCDD will be well served by our capabilities.”For additional information please contact: Ron Boustedt at Info@WatershedSecurity.com. Click here to view the list of recent Press Releases from Watershed Security, LLC
Burns W.,M Ship Co. |
Perrotti T.J.,M Ship Co. |
Todter C.,Keppel Professional Services |
Casal D.,M Ship Co. |
And 2 more authors.
3rd Chesapeake Power Boat Symposium, CPBS 2012 | Year: 2012
M-Ship Co. has developed an innovative Rapid Empirical Innovation (REI) approach to open-water ship model testing with the goal of providing a system targeted towards rapid, low cost ship design. The system is designed to provide test data quality close to that of a towing tank, at a substantially lower cost. It is capable of both smooth water drag and trim measurement as well as rough water drag and motions assessment, comparable to towing tank measurements. After developing, testing, and refining the testing platform, and its systems, a series of arbitrary models (including the classic Series 62 model) of widely varying concepts were designed, produced, and tested using the REI system. This process consisted of an extensive set of smooth water, and rough water tests to characterize the models as well as the testing platform. The final phase of the program was validation, by taking three of the models (including the historically tested Series 62 model) to the NSWCCD David Taylor Model Basin (DTMB) for both smooth and rough water testing so comparisons could be made between the towing tank data (DTMB) and the REI system. All phases of platform development and data quality investigation were successfully completed in 2011. Our report will summarize M Ship's testing methodology and comparative results.
Maribo D.,NSWCCD |
Gavrilash M.,NSWCCD |
Reilly P.J.,NSWCCD |
Lynch W.A.,Raven LLC |
Sondergaard N.A.,BMT Syntek Technologies Inc.
Electrical Contacts, Proceedings of the Annual Holm Conference on Electrical Contacts | Year: 2010
Liquid Metals were used to make sliding electric contacts by Michael Faraday, in 1832. In contrast to solid sliding electric contacts, liquid metals provide uniform coverage to a moving surface and therefore have very low electrical contact losses and are essentially wear free. However, being liquid, the contacts are subject to hydrodynamic instabilities which can cause the liquid to leave the electric contact region and therefore not function. Theoretical considerations suggest these instabilities can become worse at large diameters (1-2 meters). This paper describes an apparatus that was designed to investigate the operation of liquid metal sliding electrical contacts in large magnetic fields. The apparatus consist of a large diameter sliding contact surface rotated by an external drive motor and connected to a direct current power supply of 100,000 amps. The sliding contact apparatus sits in a background magnetic field of up to 2T which can be arbitrarily oriented by changing the current in a superconductive magnet system with a novel dipole-quadrupole configuration. Preliminary data are presented on operation of the test apparatus with liquid metal filled fibers. The Slipring resistance was between 0.1 and 0.2 micro-ohms. Circulating current losses were measured near 3kW for a 2.2 T radial magnetic field at 100 rpm while losses in 1.6T axial magnetic fields were around a kW at similar speed. The apparatus was operated for several months and no instabilities were observed in the large diameter collector. ©2010 IEEE.
Nikoukhah R.,French Institute for Research in Computer Science and Automation |
Campbell S.L.,North Carolina State University |
International Journal of Systems Science | Year: 2010
The methodology of auxiliary signal design for robust fault detection based on a multi-model (MM) formulation of normal and faulty systems is used to study the problem of incipient fault detection. The fault is modelled as a drift in a system parameter, and an auxiliary signal is to be designed to enhance the detection of variations in this parameter. It is shown that it is possible to consider the model of the system with a drifted parameter as a second model and use the MM framework for designing the auxiliary signal by considering the limiting case as the parameter variation goes to zero. The result can be applied very effectively to many early detection problems where small parameter variations should be detected. Two different approaches for computing the test signal are given and compared on several computational examples. © 2010 Taylor & Francis.
Chang III P.A.,Naval Surface Warfare Center Carderock Division |
Vargas A.,NSWCCD |
Jiang M.,NSWCCD |
Lummer D.,NSWCCD |
Mahesh K.,University of Minnesota
20th AIAA Computational Fluid Dynamics Conference 2011 | Year: 2011
A high-accuracy large eddy simulation (LES) is applied to flows over a sphere and an underwater vehicle. Both objects have relatively weak separated stern flows that may depend upon the accurate resolution of turbulence structures in the attached flow regions upstream of the separation point. For the sphere we compute flows over a range of Reynolds numbers from sub- to super-critical (Re = 1×104 to Re = 1:14×106, respectively) for which we obtain decent agreement for the separation location, pressure distributions and integrated forces. Long time series data shows evidence of low-frequency shedding phenomena. We perform LES on the Advanced SEAL Delivery System (ASDS), an underwater vehicle with a rounded-rectangular cross section and stern slope that promotes weak flow separations. We compute the fully resolved flow over the ASDS for length-based Reynolds numbers 128 × 103, 256 × 103 and 512 × 103. We show that the mean flow fields over the attached flow region are reasonable in that the boundary layer profiles, shape factors and skin friction agree with other examples of developing turbulent boundary layer flows. The instantaneous flow fields exhibit near-wall turbulence structures with the correct length scales and dynamics as compared with the wall-bounded turbulent flow literature. The separation point moves aft and the extent of the separation region decreases markedly as the Reynolds number increases.
Roemer M.J.,Impact Technologies, LLC |
Palmer C.A.,Impact Technologies, LLC |
Bharadwaj S.P.,Impact Technologies, LLC |
Proceedings of the ASME Turbo Expo | Year: 2010
Energy conservation measures currently employed by U.S. Navy surface combatants require labor-intensive, time-consuming data entry from which fuel curves are generated to drive each ship's propulsion plant machinery alignment. From these rudimentary curves optimal transit speeds, configurations, and refueling requirements are determined for specific operational demands and mission profiles. This paper describes an automated process for optimizing shipboard fuel consumption rates by integrating advanced diagnostic and maintenance optimization techniques with the onboard data information system. The automated energy conservation decision support system described herein addresses fossil fuel propulsion (gas turbines, steam turbines, and diesel engines), power generation and auxiliary systems. The software tool consists of diagnostic, fuel management, and maintenance modules. The diagnostic module tracks and trends the health state of components that use fuel (and their supporting systems) to provide real-time information on the impact of their current condition on fuel consumption. The fuel management module automates data collection and the generation of fuel curves through open-systems architecture communication with ICAS. It also enables planning by recommending an optimal machinery configuration to minimize fuel consumption based on either speed or time to destination constraints. Additionally, a fuel management module provides real-time information on fuel consumption and optimizes the load of each component based on its health condition, operating requirements and the number and condition of similar components. Finally, overall decision support comes from the maintenance management module that tracks the maintenance actions being performed on fuel consuming systems and recommends future maintenance to be performed (from a fuel conservation standpoint) based on current health information. Copyright © 2010 by ASME.
Amromin E.L.,Mechmath LLC |
Metcalf B.,NSWCCD |
Journal of Fluids Engineering, Transactions of the ASME | Year: 2011
Friction on a surface covered by an air cavity is much less than friction in water but there is a resistance penalty caused by the cavity tail oscillations. Nevertheless, there is a method for designing the ship bottom form for suppressing these oscillations. This study describes the design method and calm water towing tank tests for a ship with a bottom ventilated air cavity operating at Froude range 0.45
Amromin E.,Mechmath LLC |
Karafiath G.,NSWCCD |
Journal of Ship Research | Year: 2011
The goal herein is ship drag reduction by air bottom cavitation in the moderate range of Froude number Fr (0.4 < Fr < 0.65) in both calm water and in waves. A ship hull with a bottom niche terminating in a cavity locker/seal (suppressing cavity tail oscillations and reducing the air escape from the cavity) was designed using nonlinear ideal fluid theory. The wave impact on the cavity shape and drag reduction was estimated with a novel analytical approach that takes into account the air compressibility in the cavity and air entrainment by the water. The model drag was measured in the Naval Surface Warfare Center linear tow tank at different drafts in calm water and in waves. The baseline configuration was with the niche closed by a flat cover. The attained total drag reduction at 0.45 < Fr < 0.63 was up to 25%, whereas the air supply power was under 4% of the gain in the required propulsion power. The air cavity was stable in waves (up to sea state 5 for a 90 meter ship) and the effectiveness of drag reduction by cavitation in seaway was greater than in calm water due to smaller wave-induced additional drag of the ship with air bottom cavity. Two identical models were built and tested also as a seatrain. However, the percentage drag reduction due to cavity ventilation in the seatrain configuration was less than for a single hull. The need for fine tuning the air supply distribution between the hulls was found.
Shih T.-M.,University of Maryland University College |
Thamire C.,University of Maryland University College |
Sung C.-H.,NSWCCD |
Ren A.-L.,Zhejiang University
Numerical Heat Transfer; Part A: Applications | Year: 2010
A comprehensive survey of the literature in the area of numerical heat transfer (NHT) published between 2000 and 2009 has been conducted. The journals surveyed in this review include Numerical Heat Transfer (both parts A and B), ASME Journal of Heat Transfer, International Journal of Heat and Mass Transfer, and, selectively, and International Journal for Numerical Methods in Fluids. During the survey, the authors noticed that some terminology and jargon have been used extensively, but sometimes appear somewhat non-unified. Galerkin method is a numerical technique in which the weighting functions are chosen to be the same as the basis functions. If the basis functions are piecewise functions, such as x and 1-x within [0, 1] and zero elsewhere in 1-D examples, then the method should belong to Galerkin finite element method. In the system of a channel flow, generally there are inlets and outlets and the flow is confined by surrounding walls. The fluid flows predominantly in one direction. The pressure drop is significant in comparison with the momentum changes.