| On the Density Scaling of Liquid Dynamics |
Jan 2011 |
4 pages |
| Authors:
D Fragiadakis; C M Roland; NAVAL RESEARCH LAB WASHINGTON DC MATERIALS CHEMISTRY BRANCH
|
 | Superpositioning of relaxation data as a function of the product variable TV gamma , where T is temperature, V the specific volume, and gamma a material constant, is an experimental fact demonstrated for approximately 100 liquids and polymers. Such scaling behavior would result from the intermolecular potential having the form of an inverse power law (IPL), suggesting that an IPL is a good approximation for certain relaxation properties over the ... |
|
| 3-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Fuel Cell Using Different Fuels |
Jan 2011 |
85 pages |
| Authors:
Sachin L Puthran; MISSOURI UNIV OF SCIENCE AND TECHNOLOGY ROLLA
|
| Solid oxide fuel cell (SOFC) technology has been of great interest over many years due to its flexibility in using different fuels for operation; including the fundamental fuel i.e. Hydrogen. Various computational and numerical models have been developed along with experimental work to evaluate the performance as well as to identify and overcome the problems faced in the development of SOFC's. In an attempt to achieve efficient operation with respect ... |
|
| Separation Control with Nanosecond Pulse Driven Dielectric Barrier Discharge Plasma Actuators |
Jan 2011 |
43 pages |
| Authors:
Jesse Little; Keisuke Takashima; Munetake Nishihara; Igor Adamovich; Mo Samimy; ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
| The efficacy of dielectric barrier discharge (DBD) plasmas driven by high voltage (approximately 15 kV) repetitive nanosecond pulses approximately 100 ns FWHM) for flow separation control is investigated experimentally on an airfoil leading edge up to Re=1x106 (62 m/s). Unlike AC-DBDs, the nanosecond pulse driven DBD plasma actuator transfers very little momentum to the neutral air, but generates compression waves similar to localized arc filament plasma actuators. A complex pattern ... |
|
| AHPCRC (Army High Performance Computing Rsearch Center) Bulletin. Volume 1, Issue 4 |
Jan 2011 |
29 pages |
| Authors:
HIGH PERFORMANCE TECHNOLOGIES INC RESTON VA
|
| The Army High Performance Computing Research Center, a collaboration between the U.S. Army and a consortium of university and industry partners, develops and applies high performance computing capabilities to address the Army s most difficult scientific and engineering challenges. AHPCRC also fosters the education of the next generation of scientists and engineers including those from racially and economically disadvantaged backgrounds in the fundamental theories and best practices of simulationbased engineering ... |
|
| Nesting a Nonhydrostatic Model in a Hydrostatic Model: The Boundary Interface |
Jan 2011 |
11 pages |
| Authors:
P C Gallacher; D A Hebert; M R Schaferkotter; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEAN SCIENCES BRANCH
|
| A method is developed for adjusting the values of the prognostic variables near the interface between a nonhydrostatic, high resolution model embedded in a hydrostatic, coarser resolution model. It incorporates a method of conditioning the outer domain lateral boundary values to enforce conservation of volume when the variables are interpolated onto the inner domain grid. This is accomplished by adjusting the baroclinic normal velocities at the open boundaries after interpolation. ... |
|
| Quantifying Turbulence Microstructure for Improvement of Underwater Imaging |
Jan 2011 |
12 pages |
| Authors:
Sarah Woods; Weilin Hou; Wesley Goode; Ewa Jarosz; Alan Weidemann; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEAN SCIENCES BRANCH
|
| Enhancing visibility through scattering media is important in many fields for gaining information from the scattering medium. In the ocean, in particular, enhancement of imaging and visibility is important for divers, navigation, robotics, and target and mine detection and classification. Light scattering from particulates and turbulence in the ocean strongly affect underwater visibility. The magnitude of this degrading effect depends upon the underwater environment, and can rapidly degrade the quality ... |
|
| Nesting a Nonhydrostatic Model in a Hydrostatic Model: The Boundary Interface |
Jan 2011 |
10 pages |
| Authors:
Patrick C Gallacher; David A Hebert; Michael R Schaferkotter; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| A method is developed for adjusting the values of the prognostic variables near the interface between a nonhydrostatic, high resolution model embedded in a hydrostatic, coarser resolution model. It incorporates a method of conditioning the outer domain lateral boundary values to enforce conservation of volume when the variables are interpolated onto the inner domain grid. This is accomplished by adjusting the baroclimc normal velocities at the open boundaries after interpolation. ... |
|
| Two Dynamical System Models Based on Real-World Scenarios: A Swarming Control Model and a Surface Tension Model |
Jan 2011 |
108 pages |
| Authors:
Wangyi Liu; CALIFORNIA UNIV LOS ANGELES
|
| Dynamical systems are quite often used to describe complex real-life phenomena. In this dissertation we consider two different scenarios where we propose such models. In the first part we consider the problem of collaborative searching where agents try to search for unknown targets while keeping group formation. This scenario is observed in many animal groups, and can be applied to man-made problems like searching for mines. We use a basic ... |
|
| Dynamics and Control of Non-Smooth Systems with Applications to Supercavitating Vehicles |
Jan 2011 |
208 pages |
| Authors:
Vincent Nguyen; MARYLAND UNIV COLLEGE PARK DEPT OF COMPUTER SCIENCE
|
| The subject matter of this dissertation relates to the dynamics of non-smooth vehicle systems, and in particular, supercavitating vehicles. These high-speed underwater vehicles are designed to have sustained vaporous or ventilated gas cavities that form over the entire vehicle. In terms of the modeling, the system non-smoothness is caused by the interaction forces generated when the vehicle contacts the cavity. These planing interactions can cause stable and unstable dynamics, some ... |
|
| Video and Field Observations of Wave Attenuation in a Muddy Surf Zone |
2011 |
12 pages |
| Authors:
P. S. Pereira; L. J. Calliari; R. Holman; K. T. Holland; R. M. Guedes; C. K. Amorin; R. G. Cavalcanti; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
|
| Besides the different scales within which coastal processes manifest their energy, the majority of the world's coastal regions exhibit forms of sediment heterogeneity that are physically significant. One example of a heterogeneous environment is Cassino beach. located at the southernmost part of Brazil, a fine-grain-sized sandy beach where fluid mud sporadically is transported to the nearshore and eventually onto the beach. At this site in 2005. as part of a ... |
|
| A Lagrangian-Eulerian Approach to Modeling Homogeneous Condensation in High Density Flows (PREPRINT) |
13 Dec 2010 |
27 pages |
| Authors:
Ryan Jansen; Natalia Gimelshein; Sergey Gimelshein; Ingrid Wysong; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES
|
| A computational approach to homogeneous nucleation is proposed, based on Eulerian description of the gas phase coupled with a Lagrangian approach to the cluster phase. A continuum, Euler / Navier-Stokes solver VAC is used to model the gas transport, and a kinetic particle solver is developed in this work to simulate cluster nucleation and growth. Parameters in the new model were adjusted so as to match the known theoretical dimer ... |
|
| Radiation Measurements in Simulated Ablation Layers |
06 Dec 2010 |
28 pages |
| Authors:
Richard G Morgan; QUEENSLAND UNIV (AUSTRALIA)
|
| In this study, radiation in ablating shocklayers over a scale Stardust model at 9 km/s was measured during the 80 microsecond steady test flow produced in a high enthalpy super-orbital expansion tunnel. The presence of an ablating shock layer when an epoxy coating is used with air and nitrogen test gases is shown by spectrometric and high speed camera data, and is in agreement with previous experimental results. Shock layer ... |
|
| Design and Laboratory Tests of a Doppler Asymmetric Spatial Heterodyne (DASH) Interferometer for Upper Atmospheric Wind and Temperature Observations |
06 Dec 2010 |
12 pages |
| Authors:
John M Harlander; Christoph R Englert; David D Babcock; Frederick L Roesler; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
|
| We describe the design, fabrication and laboratory tests of a Doppler Asymmetric Spatial Heterodyne (DASH) interferometer for upper atmospheric wind and temperature observations of the O[(sup 1)D] 630 nanometer emission. The monolithic interferometer has no moving parts, a large etendue, relaxed fabrication and alignment tolerances and can measure multiple emission lines simultaneously. Laboratory measurements indicate that the design resolution and etendue were achieved and that thermal drifts can be determined ... |
|
| Contact and Impact Dynamic Modeling Capabilities of LS-DYNA for Fluid-Structure Interaction Problems |
02 Dec 2010 |
118 pages |
| Authors:
Ravi Challa; OREGON STATE UNIV CORVALLIS
|
| Fluid-structure interaction (FSI) is a very interesting and challenging multi-disciplinary field involving interaction of a movable or deformable structure with an internal or surrounding fluid flow. FSI plays a pivotal role in many different types of real-world situations and practical engineering applications involving large structural deformation and material or geometric nonlinearities. Modeling the ocean environment (deep and shallow water, and surf and beach zones), and loads and motions of platforms ... |
|
| Mathematical Fluid Dynamics of Plasma Flow Control over High Speed Wings |
Dec 2010 |
52 pages |
| Authors:
David Marshall; Alexander Fedorov; Victor Soloview; TELEDYNE SCIENTIFIC AND IMAGING LLC THOUSAND OAKS CA
|
| This report summarizes modeling of surface dielectric barrier discharge (SDBD) and flow control. A physics-based phenomenological model was used for analytical approximations of SDBD-induced body force and heat source, which were incorporated into a Navier-Stokes solver for CFD studies. Results show that a SDBD actuator can strongly affect laminar boundary layers and that tangential jets or concentrated vortices can be generated in the near-wall flow, thus making SDBD actuators attractive ... |
|
| Dynamic Failure of Sandwich Beams With Fluid-Structure Interaction Under Impact Loading |
Dec 2010 |
57 pages |
| Authors:
Ryan D McCrillis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The objective of this research is to examine the added mass effect that water has on the dynamic response of a sandwich composite under impact, particularly impact leading to failure. Because sandwich composites are much less dense than water, fluid structure interaction plays a large part in the failure. Composite samples were constructed using vacuum assisted transfer molding, with a 6.35 mm balsa core and symmetrical plain weave 6 oz ... |
|
| Waves, Hydrodynamics and Sediment Transport Modeling at Grays Harbor, WA |
DEC 2010 |
266 pages |
| Authors:
Zeki Demirbilek; Lihwa Lin; Jarrell Smith; Earl Hayter; Ernest Smith; Joseph Z. Gailani; Gregory J. Norwood; David R. Michalsen; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
|
| This numerical modeling study was performed for the purpose of addressing short- and mid-term dredge material management issues for the Federal Navigation Project at Grays Harbor (GH), Washington. Seattle District (NWS) is also currently evaluating GH navigation channel realignment in the Point Chehalis/Entrance reach because historic trends in survey data indicate this area is naturally scouring a new thalweg just north of the present channel. The realigned channel would take ... |
|
| Impact of Electrostatic and Conventional Sprayers Characteristics on Dispersion of Barrier Spray |
DEC 2010 |
11 pages |
| Authors:
Muhammad Farooq; Todd W. Walker; Bryan P. Heintschel; Wesley C. Hoffmann; Bradley K. Fritz; Vincent L. Smith; Cathy A. Robinson; Trey English; NAVY ENTOMOLOGY CENTER OF EXCELLENCE JACKSONVILLE FL
|
| A study was conducted to analyze the performance of 3 electrostatic (Electrolon BP-2.5TM Spectrum Electrostatic 4010, and Spectrum Electrostatic head on a Stihl 420) and 2 conventional (Buffalo Turbine CSM2 and Stihl 420) sprayers for barrier sprays to suppress an adult mosquito population in an enclosed area. Sprayer characteristics such as charge-mass ratio, air velocity, flow rate, and droplet spectra were measured while spraying water. Dispersion of the spray cloud ... |
|
| Reduced-Order Modeling for Optimization and Control of Complex Flows |
30 Nov 2010 |
20 pages |
| Authors:
Jeff Borggaard; Traian Iliescu; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG INTERDISCIPLINARY CENTER FOR APPLIED MATHEMATICS
|
| The primary objectives of this research were to develop reduced-order modeling methodologies for control and optimization applications. This was achieved through three specific research goals. First of all, we focused on improving the accuracy of reduced-order model simulations by including closure terms (that can be implemented in practical applications). Secondly, we used sensitivity analysis to improve the accuracy of models over ranges of parameters. Finally, we developed a better methodology ... |
|
| Numerical Simulation of Transom-Stern Waves |
22 Nov 2010 |
8 pages |
| Authors:
Randall E Hand; Miguel Valenciano; Kevin George; Tom Biddlecome; Richard Walters; Mike Stephens; Thomas T O'Shea; Kyle A Brucker; Douglas G Dommermuth; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS DATA ANALYSIS AND ASSESSMENT CENTER
|
| The flow field generated by a transom-stern hullform is a complex, broad-banded, three-dimensional phenomenon marked by a large breaking wave. This unsteady multiphase turbulent flow feature is difficult to study experimentally and simulate numerically. The results of a set of numerical simulations, which use the Numerical Flow Analysis (NFA) code, of the flow around the Model 5673 transom stern at speeds covering both wet- and dry-transom operating conditions are shown ... |
|
| Exploitation of Thermal Signals in Tidal Flat Environments |
16 Nov 2010 |
9 pages |
| Authors:
Chris Chickadel; Jim Thomson; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| The overall goal is to identify and understand the physical processes that shape and change coastal environments. Emphasis is on the application of remotely sensed infrared signals that can be compared with in situ observations and assimilated within predictive models. In tidal flat environments, major goals are detection of: geotechnical properties (e.g., sediment strength), morphologic features (e.g., channels), related hydrodynamic events (e.g., plumes). The primary objective of these joint efforts ... |
|
| NAVFAC Ocean Thermal Energy Conversion (OTEC) Project; OTEC Technology Development Report |
Nov 2010 |
|
| Authors:
Brian Cable; LOCKHEED MARTIN MS2 MANASSAS VA
|
 | The Navy views OTEC technology as a potentially viable means to reduce dependence on fossil fuel for electricity generation at bases located in tropical areas, including Naval Support Facility Diego Garcia (NSFDG), as well as naval facilities in Hawaii and Guam. The Navy's long term objective is the commercialization of OTEC technology to permit purchase of power and water from a privately developed OTEC facility at cost effective rates. Advancing ... |
|
| Spectroscopy Measurements on Ablation Testing in High Enthalpy Plasma Flows |
Nov 2010 |
47 pages |
| Authors:
Olivier P Chazot; VON KARMAN INST FOR FLUID DYNAMICS RHODE-SAINT-GENESE (BELGIUM)
|
| The objective of this work is to develop the capability of testing and characterization of ablative materials exposed to high enthalpy plasma flows including both classical and spectroscopic based measurement techniques. Two different ablative material specimens, a newly developed carbon resin composite ablator (MONA, Lockheed Martin) and a cork compound (AMORIM Cork composites), were selected to perform the measurements. A comprehensive setup of measurement techniques was applied to the Plasmatron ... |
|
| Optimization of a Three-Dimensional Diagnostic Flow Solver |
Nov 2010 |
26 pages |
| Authors:
chatt C Williamson; Yansen Wang; ARMY RESEARCH LAB ADELPHI MD COMPUTATIONAL AND INFORMATION SCIENCES DIRECTORATE
|
| In this study, we investigate the performance of a three-dimensional diagnostic flow solver. The numerical solver is profiled to find the hot spots of the code. These hot spots are then optimized for performance using techniques such as loop reordering and cache blocking. OpenMP is used to parallelize the code execution, further enhancing its performance. Finally, preliminary efforts to use NVIDIA Inc. Compute Unified Device Architecture (CUDA) programming model are ... |
|
| The Near Wake of Bluff Bodies in Stratified Fluids and the Emergence of Late Wake Characteristics |
29 Oct 2010 |
102 pages |
| Authors:
Julian A Domaradzki; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
| The primary goal of our work was to provide accurate information about velocity and density field in the near wake region of a flow around a sphere in a stratified fluid. This is a canonical configuration used in investigating a structure of stratified wakes and in numerical simulations. |
|
| Closed-Loop Control of Vortex Formation in Separated Flows with Application to Micro Air Vehicles |
25 Oct 2010 |
61 pages |
| Authors:
Tim Colonius; Morteza Gharib; Clarence W Rowley; Gilead Tadmor; David R Williams; CALIFORNIA INST OF TECH PASADENA
|
| This research is concerned with developing theory, algorithms. and applications of model -based, closed loop flow control in order to enable robust and agile flight of micro air vehicles, the efforts are centered around the application to integrated closed-loop flow and fight control for stabilization and regulations of separated flows occurring on unmanned and micro air vehicles ( UAV/MAV). |
|
| Dynamics of the Mixed Layers in Stratified Sheared Flows |
18 Oct 2010 |
21 pages |
| Authors:
Georgy Manucharyan; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| Vast verity of geophysical flows occur in density stratified fluids in a presence of sheared mean velocity profiles. Under such conditions it's been observed that vigorous turbulence leads to generation of mixed layers within the fluid, e.g. the regions of homogeneous density separated from each other by strong density gradients (interfaces). These layers could be of large vertical scales as well as of fine scales. An example of such flows ... |
|
| Finding Lagrangian Structures via the Application of Braid Theory |
16 Oct 2010 |
23 pages |
| Authors:
Michael R Allshouse; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| The ability to accurately identify regions of mixing in two dimensional systems has applications in ocean and geophysical systems, as well as granular flows. Over the last decade, much work has been put into finding coherent structures in the Lagrangian frame. Most of these methods require field data (e.g. velocity or vorticity fields) which in situations like the ocean are not readily available. However, trajectories of tracers for these systems ... |
|
| Tomographic PIV Study of the Low Re Number Flow Around a Pitching Plate with a Ramp Time History |
14 Oct 2010 |
31 pages |
| Authors:
Julio Soria; MONASH UNIV CLAYTON (AUSTRALIA)
|
| Unsteady aerodynamics in the low Reynolds number domain is of great interest in applications to Micro Air Vehicles (MAVs), especially with respect to flow over, and in the wake of, pitching airfoils. The massively separated flow over the upper surface of the pitching aerofoil allows for the production of large transient peaks of lift at this scale. This study extends our previous work to multi-dimensional (3D), multi-component (3C) measurements of ... |
|
| A New Mixing Diagnostic and Gulf Oil Spill Movement |
Oct 2010 |
5 pages |
| Authors:
Igor Mezic; S Loire; Vladimir A Fonoberov; P Hogan; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Chaotic advection has served as the paradigm for mixing in fluid flows with simple time dependence. Its skeletal structure is based on analysis of invariant attracting and repelling manifolds in fluid flows. Here we develop a finite-time theory for two-dimensional incompressible fluid flows with arbitrary time dependence and introduce a new mixing diagnostic based on it. Besides stretching events around attracting and repelling manifolds, this allows us to detect hyperbolic ... |
|
| Transition Control with Dielectric Barrier Discharge Plasmas |
OCT 2010 |
38 pages |
| Authors:
Cameron Tropea; A Duchmann; S Grundmann; TECHNISCHE UNIVERSITAET DARMSTADT (GERMANY)
|
| The long-term objective of the project is to control natural boundary-layer transition through the use of plasma actuators. Transition delay or even suppression has its merits not only in lower wall shear stress and frictional drag of laminar as opposed to turbulent boundary layers, but transition control can be instrumental in influencing flow separation, which opens avenues for significantly influencing pressure drag and wake acoustics of bluff bodies or profiles. ... |
|
| Risk-Based Computational Prototyping (Briefing Charts) |
OCT 2010 |
40 pages |
| Authors:
Philip Beran; Jose Camberos; Ned Lindsley; Bret Stanford; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIR/STRUCTURES DIV/DESIGN AND ANALYSIS METHODS BRANCH
|
| We are developing computational methods that will enable the computational design of air vehicles accounting for inherently nonlinear dynamic behaviors. These behaviors fall into two categories: behaviors that are beneficial for vehicle operation, such as could be observed for micro air vehicles propelled by wing flapping (e.g., a productive energy transfer between the unsteady vortical flow produced by a flapping wing and the associated nonlinear deformation of the wing), and ... |
|
| Hydrodynamic Forces on Spillway Torque-Tube Gates |
Oct 2010 |
13 pages |
| Authors:
Luis A de Bejar; Richard L Stockstill; ARMY CORPS OF ENGINEERS VICKSBURG MS ENGINEER RESEARCH AND DEVELOPMENT CENTER
|
| The critical hydraulic configuration for a set of torque-tube gates controlling the flow through the navigable portion of a spillway was experimentally identified. In this paper, an analytical model for the upstream pressure field on a typical gate within the set is constructed. The gate rotation from the maximum elevation gate in closed position and the hydraulic torque transmitted by the pressure field to the gate tube are formulated. Mean ... |
|
| Time-Domain Hydrodynamic Forces on Rigid Dams With Reservoir Bottom Absorption of Energy |
Oct 2010 |
11 pages |
| Authors:
Luis A de Bejar; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| In this investigation, a two-dimensional time-domain closed-form mathematical model for the hydrodynamic forces on the upstream vertical face of a given rigid dam subjected to a specified horizontal ground motion accelerogram was developed. The model includes the absorption of energy at the elastic reservoir bottom, characterized by the impedance ratio of the sub-bottom materials with respect to water . The formulated boundary-value problem is solved in Laplace's domain and subsequently ... |
|
| Impacts of Turbulence on Hurricane Intensity |
30 Sep 2010 |
5 pages |
| Authors:
Yongsheng Chen; Richard Rotunno; George H Bryan; NATIONAL CENTER FOR ATMOSPHERIC RESEARCH BOULDER CO
|
| Our recent studies have found that hurricane boundary layer turbulences, which can only be parameterized in the current weather-prediction models, play significant roles in controlling the hurricane intensity. The long-term goal of this project is thus to improve the hurricane intensity forecast by developing a more physically based turbulence parameterization scheme. The turbulence effect on the hurricane intensity can be quantified only if the turbulences can be resolved in the ... |
|
| Optical Imaging of the Nearshore |
30 Sep 2010 |
5 pages |
| Authors:
Rob Holman; OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES
|
| The long-term goal of nearshore processes research has been to develop a predictive understanding of the fluid dynamics of a random wave field shoaling over the complicated bathymetry of a natural beach, and the response of the beach to those overlying wave and current motions [Holman et al., 1990]. The format of those predictions is usually numerical predictions, merging model dynamics with inputs provided by either in-situ or remotely-sensed methods. ... |
|
| Observing the Evolution of Typhoon Wakes |
30 Sep 2010 |
3 pages |
| Authors:
Steven R Jayne; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| The long-term goal of this work is to observe, understand, quantify and parameterize upper-ocean mixing for use in global ocean modeling. Our research program is to observe the temporal and spatial evolution of typhoon cold wakes, in particular we plan to directly observe the mixing associated with turbulence generated by the strong air-sea interaction in a typhoon. These observations will be used to make quantifiable assessments of mixed layer models ... |
|
| Hydrostatic and Nonhydrostatic Nested Modeling of Straits in the Philippines Archipelago |
30 Sep 2010 |
8 pages |
| Authors:
Patrick C Gallacher; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEAN SCIENCES BRANCH
|
| This study utilizes nested nonhydrostatic models embedded in hydrostatic models to simulate and predict the submesoscale dynamics of straits at high spatial and temporal resolutions. The goal of this work is to understand the submesoscale dynamics of straits and the impact of these dynamics on the throughflow in the straits. The Navy requires the ability to forecast features and circulations forced by these dynamics on scales that impact naval operations, ... |
|
| Development of a Highly Efficient and Accurate Wind-Wave Simulation Framework for Operational Data Assimilation |
30 Sep 2010 |
8 pages |
| Authors:
Lian Shen; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF CIVIL ENGINEERING
|
| This research aims at developing a highly efficient yet accurate computation framework for simulation and prediction of wave and wind coupled motions with wave phases being resolved, which will lead to an advanced data assimilation tool to provide more comprehensive environmental input for naval applications. Our ultimate goal is to pave the way for developing an operational tool for the Navy to use for ocean-wave-atmosphere battlespace sensing and prediction with ... |
|
| Large-Eddy Simulations of Tropical Convective Systems, the Boundary Layer, and Upper Ocean Coupling |
30 Sep 2010 |
6 pages |
| Authors:
Eric D de Skyllingstad; Simon Szoeke; OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES
|
| Improve operational numerical weather prediction (NWP) models to more accurately simulate the interaction of tropical deep convection and atmospheric and oceanic boundary layers. Investigate tropical convection and upper ocean circulations on scales from 100 m to 200 km. Elucidate specifically how the ocean mixed layer responds to forcing from atmospheric convection such as wind and precipitation, and thus how surface fluxes depend on the history of convective events. Perform high-resolution ... |
|
| Modeling the Effects of Anisotropic Turbulence and Dispersive Waves on Oceanic Circulation and their Incorporation in Navy Ocean Models |
30 Sep 2010 |
6 pages |
| Authors:
Boris Galperin; UNIVERSITY OF SOUTH FLORIDA SAINT PETERSBURG COLL OF MARINE SCIENCE
|
| Our long-term goals are to advance the understanding and modeling capabilities of the dynamics and mixing in oceanic and atmospheric turbulent flows on small and large scales. The main emphasis is put on the development of analytical tools and their transition to practical applications useful for Navy operations. Our objectives encompass three areas: improving understanding of geophysical turbulent flows affected by anisotropy and waves using analytical tools; improving understanding of ... |
|
| Dynamics and Modeling of Turbulent Mixing in Oceanic Flows |
30 Sep 2010 |
10 pages |
| Authors:
Subhas K Venayagamoorthy; COLORADO STATE UNIV FORT COLLINS
|
| The long-term goal of this research is to refine and extend simple (existing) model parameterizations for turbulent diapycnal mixing for use in large scale numerical ocean models where such processes occur at the subgrid-scale. From a scientific view point, the goal is to obtain new insights into the dynamics of stratified turbulence that will translate into simple effective parameterizations for use in ocean models. The primary objective of this project ... |
|
| Variability of Irradiance in the Wave Boundary Layer |
30 SEP 2010 |
7 pages |
| Authors:
W. S. Pegau; Hemantha W. Wijesekera; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Our primary goal is improve our understanding of the role of surface waves, bubble clouds, and nearsurface oceanic processes on the spatial distribution of oceanic irradiance. |
|
| Monitoring Bloom Dynamics of a Common Coastal Bioluminescent Ctenophore |
30 SEP 2010 |
11 pages |
| Authors:
Edith A. Widder; OCEAN RESEARCH AND CONSERVATION ASSOCIATION FORT PIERCE FL
|
| The long-term objective is to develop predictive models of bioluminescence potential in the coastal zone environment. OBJECTIVES: In the coastal zone, watershed run-off and discharge of submarine ground-water can profoundly impact growth conditions of bioluminescent plankton on very short space and time scales. Bioluminescent blooms include dinoflagellate red tides, which are occurring more frequently, lasting longer and extending further off shore due to excessive nutrient loading from land-based run-off. Bioluminescent ... |
|
| Convection and Shear Flow in TC Development and Intensification |
30 SEP 2010 |
5 pages |
| Authors:
C. P. Chang; H. C. Kuo; C. H. Liu; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF METEOROLOGY
|
| To study the dynamic processes of tropical cyclone (TC) development in the western North Pacific through field observational data and theoretical modeling. The objectives are: (1) to study the convection and vorticity generations in the vortex environment that may lead to the development and intensification of tropical cyclone; (2) to study the development and evolution of deep moist mesoscale convective system subject to strain effect due to the horizontal shear ... |
|
| Evaluation and Improvement of High-resolution Mesoscale Models on Boundary Layer Simulations Using Ground-based Observations |
30 SEP 2010 |
9 pages |
| Authors:
Qing Wang; Melinda S. Peng; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF METEOROLOGY
|
| The long-term goal of the proposed work is to improve the physical parameterizations and wind forecast from high-resolution COAMPS. This is done through analyses of a large amount of data from a dense measurement network located the coastal Florida peninsula and through testing and evaluation of COAMPS simulations. The objectives of this year's work were to in-depth analyses of the tower observations to calculate turbulence fluxes and surface roughness length ... |
|
| NOGAPS Semi-Lagrangian |
30 SEP 2010 |
9 pages |
| Authors:
Timonthy F. Hogan; NAVAL RESEARCH LAB MONTEREY CA
|
| The long-term goal of this project is to develop new dynamical core that would enable the Navy Operational Global Atmospheric Prediction System (NOGAPS) to achieve higher horizontal and vertical resolution, higher vertical extent, increase meteorological skill, and additional predictive constituents, all without an appreciable increase in run time efficiency. The objective of this project is to develop and transition semi-Lagrangian/semi-implicit (SL/SI) integration algorithm into the NOGAPS. The SL/SI numerical algorithm ... |
|
| Apparatus for Electro-Magneto-Hydro-Dynamic Energy Harvesting |
27 Sep 2010 |
41 pages |
| Authors:
Steven R Snarski; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An electro-magneto-hydro-dynamic electrical power source is constructed from a platform having a surface on which a permanent magnet is attached. The permanent magnet comprising a width and a length measured perpendicular to the width. A pair of electrodes are disposed running along the length of the permanent magnet and are spaced from each other by the width of the permanent magnet. An electric load is provided in communication with the ... |
|
| Investigation of Unsteady Flow Physics around Blunt Shaped MAV using CFD |
24 Sep 2010 |
122 pages |
| Authors:
Moon-Sang Kim; Ji-Woong Kim; KOREAN AEROSPACE UNIV GOYANG-CITY (KOREA)
|
| Unsteady flow past three-dimensional blunt bodies such as sphere, rectangular parallelepiped, and circular cylinder has been numerically analyzed using Fluent to offer a design guideline for Micro Air Vehicle. Three-dimensional Navier-Stokes equations are solved with Large Eddy Simulation turbulence model. Three different aspect ratios of 1.0, 1.5, and 2.0 were selected to determine the effect of geometric shape on the unsteady flow physics in the Reynolds numbers ranging from 1000 ... |
|
| Electrochemical Buoyancy Engine for Autonomous Undersea Platforms |
14 Sep 2010 |
15 pages |
| Authors:
Thomas S Ramotowski; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| An electrochemical engine for buoyancy is provided with the engine having a water-tight and gas-tight chamber containing a volume of seawater. The electrochemical buoyancy engine contributes electrons for reduction of hydrogen protons in the seawater using a sufficient voltage applied to an anode and a cathode disposed in the seawater. The generated hydrogen gas is held in the chamber to provide the desired buoyancy and can be vented to adjust ... |
|
Fluid Mechanics
