Many authors at criticizing the conventional explanation of aerodynamic lift based on Bernoulli's law commit the same mistake laying within the scope of mechanics and ignoring the effects of viscosity in the generation of forces. Because it is an irreversible process, we affirm that it is not possible to generate lift without increasing entropy. And for an increase of entropy it must be considered the viscosity and vorticity.
Topics: viscosity, vorticity, lifting, entropy.
Charts of potential vorticity (q) within four different density layers, calculated from an eddy resolving global ocean general circulation model, are presented for the Atlantic, Pacific, and Indian Ocean Basins. Potential Vorticity is evaluated as q = (f/p)*(delta sigma/delta z), a formulation that is valid for large, slow scales and allows it to be readily calculated from model output. Here, f is Coriolis, p in situ density, sigma the potential density referred to the sea surface, and z the...
Topics: Oceanography, Numerical modeling, Potential vorticity
Mendeley Climate Change Library
19
19
Jul 6, 2019
07/19
by
Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma; Libin Ma
texts
eye 19
favorite 0
comment 0
Variability of the Kuroshio path to the south of Japan plays a central role in the local climate change and exerts tremendous influences on the local atmosphere and ocean. In this study, the response of ocean dynamics, in terms of the eddy kinetic energy (EKE), potential vorticity (PV), relative vorticity, and eddy-mean flow interaction, to the Kuroshio path change is discussed. Kuroshio path south of Japan includes the near-shore non-large meander (nNLM), the off-shore non-large meander...
Topics: Eddy kinetic energy, Kuroshio paths, eddy-mean flow interaction, potential vorticity, relative...
An upper-level trough that transited the Black Sea to the lee side of the Middle Taurus Mountains in Southern Turkey is analyzed over the course of three days, from 1200 UTC 17 February to 0000 UTC 20 February 2015. Analysis of this storm, using CFSR re-analysis output as a means to identify a cut-off, upper-level low, with associated downstream sensible weather in the Tigris-Euphrates River Valleys, is a crucial first step in locating a quasi-stationary system. This type of an anomalous event...
Topics: lee cyclogenesis, synoptic, mesoscale, potential vorticity
The term tropical transition (TT) is used to describe the formation of a tropical cyclone from an extratropical precursor. The overarching goal of this thesis is to re-examine TT in the western North Pacific. This is accomplished via the synthesis of a subjective climatology of all tropical cyclones (TCs) from 20022008 and a case study analysis of ensemble prediction data for the particularly intriguing event of TS 16W in September of 2008. The climatological analysis indicated that TT events...
Topics: Tropical Cyclones, Tropical Transition, Potential Vorticity
23
23
Dec 1, 2017
12/17
by
Kiran
image
eye 23
favorite 0
comment 0
The evolution of vorticity in the basin is suggestive of strong shear in the flow during different times of the year and further indicates the presence of low frequency geophysical waves (such as westward propagating Rossby waves, Kelvin waves, etc.) and other transient eddies.
Topics: Andaman Sea, Relative Vorticity, Kelvin wave, Rossby Wave
Submesoscale turbulence in the nearshore is observed with purpose-built drifters to perform Lagrangian measurements of the vorticity and divergence of flows with length scales under 300 meters and on-time scales of a few minutes to a few hours. Drifters are designed with an inexpensive GPS datalogger with position error of a few centimeters and velocity error of a few centimeters per second. An accelerometer is added for measuring the rotation rate of the drifters. The drifters are fitted with...
Topics: nearshore, vorticity, divergence, drifter, DKP, dynamic kinematic properties
Hydrographic data has traditionally been used only to determine dynamical features, specifically dynamic topography and geostrophic currents relative to an assumed level of no motion. However, the assumption of geostrophic balance has been questioned because of the neglect of ageostrophic effects. Measuring vorticity and vertical motion has always been technically demanding and costly. Due to the importance of these parameters new techniques have been developed, among them a diagnostic...
Topics: Three dimensional vorticity, C-vector, California current, Y function
Using the Climate Forecast System Reanalysis (CFSR) dataset, the synoptic environment of six historical coastally trapped wind reversals (CTWR) along the California coast is examined. Building on the Mass and Bond climatology of 1996, the study uses potential vorticity (PV) as a proxy for the coastal jet and seeks to characterize the forcing of the CTWRs by analyzing their 950-mb potential vorticity plumes. The study also pursues the ability to separate geostrophically-balanced wind reversals...
Topics: coastally trapped wind reversal, potential vorticity, PV inversion, coastal meteorology
625
625
May 28, 2011
05/11
by
Paliwoda, L
texts
eye 625
favorite 0
comment 0
This document contains the procedure and the test results of the Advanced Microwave Sounding Unit-A (AMSU-A) Earth Observing System (EOS) Project, assembly part number 1356008-1, serial number 202, Electromagnetic Interference (EMI) and Electromagnetic Susceptibility (EMC) qualification test. The test was conducted in accordance with the approved EMI/EMC Test Plan/Procedure, Specification number AE-26151/8B, dated 10 September 1998. Aerojet intends that the presentation and submittal of this...
Topics: VORTICITY, ATMOSPHERIC GENERAL CIRCULATION MODELS, LAGRANGIAN FUNCTION, ADVECTION, NONLINEARITY,...
4
4.0
texts
eye 4
favorite 0
comment 0
Two-dimensional laminar incompressible flow governing equation is solved numerically to gain insight into flow separation and recirculation of flow processes in an L-shape lid driven cavity. Stream function vorticity formulation of Navier equation is solved with clustered grids on physical domain. The hydrodynamic study is carried out for different Reynolds number. It is found that at Re center becomes independent of Reynolds number. Velocity contours are presented for different Reynolds...
Topics: L-Shape Lid Driven Cavity, Vortex Flow, Wall Vorticity, Velocity Vector.
Using data compiled by the National Weather Service Ocean Prediction Center, a hurricane force extratropical cyclone climatology is created for three cold seasons. Using the criteria of Sanders and Gyakum (1980), it is found that 75% of the 259 storms explosively deepened. The frequency maximum in the Atlantic basin is located to the southeast of Greenland. In the Pacific, two maxima to the east of Japan are identified. These results are in good agreement with previous studies, despite...
Topics: Extratropical Cyclones, Hurricane, Vorticity, Climatology, Explosive Deepening, Composite, Anomaly,...
162
162
Jun 9, 2011
06/11
by
Albrecht, Bruce; Sharon, Tarah; Jonsson, Haf; Minnis, Patrick; Minnis, Patrick; Ayers, J. Kirk; Khaiyer, Mandana M
texts
eye 162
favorite 0
comment 0
In this study, aircraft observations from the Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter are used to characterize the variability in drizzle, cloud, and aerosol properties associated with cloud rifts and the surrounding solid clouds observed off the coast of California. A flight made on 16 July 1999 provided measurements directly across an interface between solid and rift cloud conditions. Aircraft instrumentation allowed for measurements of aerosol, cloud droplet,...
Topics: FLOW DISTRIBUTION, EJECTORS, TURBULENCE, MIXERS, TABS (CONTROL SURFACES), VORTICITY, VELOCITY...
179
179
May 23, 2011
05/11
by
Moses, Julianne I.; Allen, Mark; Gladstone, G. Randal
texts
eye 179
favorite 0
comment 0
We have modeled the photochemical evolution of the sulfur containing species that were observed in Jupiter's stratosphere after the Shoemaker Levy 9 (SL9) impacts. We find that most of the sulfur is converted to S8 in the first few days. Other important sulfur reservoirs are CS, whose abundance increases markedly with time, and possibly H2CS, HNCS, and NS, whose abundances depend on kinetic reaction rates that are unknown at the present. We discuss the temporal variation of the major sulfur...
Topics: HYPOTHESES, VORTICITY, ERRORS, DATA ACQUISITION, THREE DIMENSIONAL MODELS, MIXING LAYERS (FLUIDS)
194
194
Jun 9, 2011
06/11
by
Lim, K. B.; Giesy, D. P
texts
eye 194
favorite 0
comment 0
Given measurement data, a nominal model and a linear fractional transformation uncertainty structure with an allowance on unknown but bounded exogenous disturbances, easily computable tests for the existence of a model validating uncertainty set are given. Under mild conditions, these tests are necessary and sufficient for the case of complex, nonrepeated, block-diagonal structure. For the more general case which includes repeated and/or real scalar uncertainties, the tests are only necessary...
Topics: COMPUTATIONAL FLUID DYNAMICS, AERODYNAMIC STALLING, TURBULENT FLOW, BOUNDARY LAYER SEPARATION,...
402
402
Jun 21, 2010
06/10
by
Lynnworth, L. C.; Patch, D. R
texts
eye 402
favorite 0
comment 0
Ultrasonic measurement of core material temperature in nuclear rocket engines
Topics: BUOYANCY, TORNADOES, VORTICITY EQUATIONS, CONSERVATION EQUATIONS, CYCLONES, EQUATIONS OF MOTION,...
The C-vector method is used to determine the three-dimensional pseudo-vorticity field of the East Greenland Current by using a CTD data set acquired during the 1984 Northwind cruise. The value of the ageostrophic pseudo- vorticity, the total (geostrophic and ageostrophic) pseudo vorticity and the vertical component of the C-vector curl, Psi, can be calculated by the C-vector method. From these values the pseudo-vorticity can be investigated for the East Greenland Current. Additionally, the...
Topics: C-Vector, East Greenland Polar Front, Ageostrophic Pseudo-vortidity, Total Pseudo-vorticity
284
284
Jul 25, 2010
07/10
by
Kim, Namsoo P.; Stanbery, Billy J.; Gale, Ronald P.; Mcclelland, Robert W
texts
eye 284
favorite 0
comment 0
The tandem cells consisting of GaAs single crystal and CuInSe2 polycrystalline thin films are being developed under the joint program of the Boeing Co. and Kopin Corp. to meet the increasing power needs for future spacecraft. The updated status of this program is presented along with experimental results such as cell performance, and radiation resistance. Other cell characteristics including the specific power of and the interconnect options for this tandem cell approach are also discussed.
Topics: COMPUTATIONAL FLUID DYNAMICS, REYNOLDS NUMBER, SPHERICAL HARMONICS, THREE DIMENSIONAL MODELS,...
Detection and tracking of submarines by acoustic means alone has become increasingly difficult due to quieter submarines, which underscores the need for non-acoustic detection methods. One hydrodynamic method available is through wake detection and the tracking of the resulting vortices created by the turbulence. Until now, it has been assumed that these vortices have large enough Rossby numbers such that the rotation of the Earth can be ignored. This study examines the vortices that persist in...
Topics: pancake vortices, stratified wake, late wake, rotation, Coriolis force, cyclonic and anticyclonic...
183
183
May 29, 2011
05/11
by
Jonsson, Ari K.; Muscettola, Nicola; Morris, Paul H.; Rajan, Kann
texts
eye 183
favorite 0
comment 0
In May 1999, as part of a unique technology validation experiment onboard the Deep Space One spacecraft, the Remote Agent became the first complete autonomous spacecraft control architecture to run as flight software onboard an active spacecraft. As one of the three components of the architecture, the Remote Agent Planner had the task of laying out the course of action to be taken, which included activities such as turning, thrusting, data gathering, and communicating. Building on the...
Topics: TRAPPING, VORTICES, VORTEX SHEETS, FLOW DISTRIBUTION, VORTICITY, TRANSLATIONAL MOTION, FLUID...
32
32
texts
eye 32
favorite 0
comment 0
In this paper we systematically investigate strong interactions between two like- signed quasi-geostrophic vortices containing different uniform potential vorticity. The interaction depends on six parameters: the potential vorticity ratio between the two vortices, their volume ratio, their individual height-to-width aspect ratio, their vertical offset, and their horizontal separation distance. We first determine the conditions under which a strong interaction may occur. To that end, we...
Topics: quasi-geostrophic vortices, potential vorticity, barotropic vortices, contour-advective...
259
259
Jun 11, 2011
06/11
by
Scambos, T. A.; Bohlander, J. A.; Shuman, C. A.; Skvarca, P
texts
eye 259
favorite 0
comment 0
Ice velocities derived from five Landsat 7 images acquired between January 2000 and February 2003 show a two- to six-fold increase in centerline speed of four glaciers flowing into the now-collapsed section of the Larsen B Ice Shelf. Satellite laser altimetry from ICEsat indicates the surface of Hektoria Glacier lowered by up to 38 /- 6 m a six-month period beginning one year after the break-up in March 2002. Smaller elevation losses are observed for Crane and Jorum glaciers over a later...
Topics: CONVECTION, ATMOSPHERIC CIRCULATION, ATMOSPHERIC MODELS, CLOUD PHYSICS, VORTICITY, TROPICAL...
398
398
Jul 9, 2010
07/10
by
MACKENTHUN, W
texts
eye 398
favorite 0
comment 0
THE INSTALLATION AND CHARACTERISTICS OF A WINDMILL POWER GENERATION PLANT ARE DISCUSSED. THE METEOROLOGICAL PARAMETERS OF THE GERMAN NORTH SEA COAST WHICH INFLUENCED THE LOCATION OF THE WINDMILL POWER GENERATING SYSTEM ARE ANALYZED. THE REGULATING DEVICES FOR COMPENSATING FOR CHANGES IN WIND VELOCITY ARE DESCRIBED. RESULTS OF THE POWER GENERATION OPERATION FOR THE YEAR 1950 ARE TABULATED.
Topics: CONVECTION, FLUID DYNAMICS, MASS FLOW, SOLAR ROTATION, CONVECTIVE FLOW, SOLAR RADIATION, SURFACE...
227
227
Oct 29, 2009
10/09
by
NASA/Goddard Space Flight Center Scientific Visualization Studio
movies
eye 227
favorite 0
comment 0
The polar vortex is an atmospheric regional event that isolates polar air from the air at temperate latitudes, producing conditions favorable for wintertime polar ozone depletion and other chemical perturbations. The location, size, and shape of the polar vortex is derived from potential vorticity (PV) data. Note: This animation shows a flat map version of the southern polar vortex at 550 degrees Kelvin during part of 2004. Animator: Eric Sokolowsky (GST), Lori Perkins (NASA/GSFC). Scientist:...
Topics: Atmosphere, Pole, Earth Science, Atmosphere, Atmospheric Winds, Vorticity, Location, Antarctica,...
Source: http://svs.gsfc.nasa.gov/goto?3098
264
264
May 31, 2011
05/11
by
Das, Sajal K.; Biswas, Rupa
texts
eye 264
favorite 0
comment 0
In a distributed-computing environment, it is important to ensure that the processor workloads are adequately balanced. Among numerous load-balancing algorithms, a unique approach due to Dam and Prasad defines a symmetric broadcast network (SBN) that provides a robust communication pattern among the processors in a topology-independent manner. In this paper, we propose and analyze three novel SBN-based load-balancing algorithms, and implement them on an SP2. A thorough experimental study with...
Topics: FLUID MECHANICS, LEADING EDGES, AIRFOILS, SEPARATED FLOW, CURVATURE, VORTICITY, DEFORMATION, ANGLE...
262
262
May 23, 2011
05/11
by
Moore, T. E.; Waite, J. H., Jr.; McComas, D. J.; Nordholdt, J. E.; Thomsen, M. F.; Berthelier, J. J.; Robson, R; Chappell, C. R.; Chandler, M. O.; Fields, S. A.; Pollock, C. J.; Reasoner, D. L.; Young, D. T.; Burch, J. L.; Eaker, N.
texts
eye 262
favorite 0
comment 0
The Thermal Ion Dynamics Experiment (TIDE) and the Plasma Source Instrument (PSI) have been developed in response to the requirements of the ISTP Program for three-dimensional (3D) plasma composition measurements capable of tracking the circulation of low-energy (0-500 eV) plasma through the polar magnetosphere. This plasma is composed of penetrating magnetosheath and escaping ionospheric components. It is in part lost to the downstream solar wind and in part recirculated within the...
Topics: MIXING LAYERS (FLUIDS), VORTICITY, JET MIXING FLOW, TURBULENT MIXING, COMPUTATIONAL GRIDS,...
In February 2004, a significant cold surge from eastern Europe extended southward over the Aegean Sea and as far south as the northern coasts of Egypt and Libya. The system examined in this study caused over 45 cm of snowfall in Souda Bay, Crete, which significantly impacted operations at Naval Support Activity Souda Bay. The extratropical wave associated with the cold surge could be classified as a classic life-cycle 1 wave break. The wave-breaking event is linked to successive cyclogenesis...
Topics: Extratropical Cyclone, Souda Bay, Crete, Genoa Low, Cold Surge, Rossby Wave Break, Dynamic...
368
368
May 30, 2011
05/11
by
Salute, Joan; Bull, Jeff; Rasky, Dan; Keese, Davi
texts
eye 368
favorite 0
comment 0
On September 28, 2000 the SHARP-B2 flight experiment was launched from Vandenberg Air Force Base, California. SHARP-B2 is the 2nd Ballistic flight test in the SHARP (Slender Hypervelocity Aerothermodynamic Research Probes) program which develops and tests new thermal protection materials and sharp body concepts. The flight tested Ultra-High Temperature Ceramics (UHTCs), which may radically change the design and performance of future aerospace vehicles. The new designs may overturn an age-old...
Topics: AEROELASTICITY, CONVERGENCE, AERODYNAMIC CHARACTERISTICS, EQUATIONS OF MOTION, EIGENVALUES, DEGREES...
Three existing and two new excitation magnitude scaling options for active separation control at Reynolds numbers below one Million. The physical background for the scaling options was discussed and their relevance was evaluated using two different sets of experimental data. For F+ approx. 1, 2D excitation: a) The traditional VR and C(mu) - do not scale the data. b) Only the Re*C(mu) is valid. This conclusion is also limited for positive lift increment.. For F+ > 10, 3D excitation, the...
Topics: NASA Technical Reports Server (NTRS), ACTIVE CONTROL, REYNOLDS NUMBER, EXCITATION, SELECTION,...
5,815
5.8K
Jul 11, 2010
07/10
by
Bornemann, W. E.; Surber, T. E
texts
eye 5,815
favorite 1
comment 0
An overview of the wind tunnel program is given and aerodynamic characteristics of the final configuration are described. Aerodynamic parameters critical to definition of Orbiter entry control and performance are identified. Trim capability and stability and control characteristics are discussed at critical regions in the entry trajectory. Methods are described to define reaction control rocket effectiveness and aerodynamic interactions during the initial portion of entry. At hypersonic speeds,...
Topics: ANGLES (GEOMETRY), AXISYMMETRIC FLOW, EXTERNALLY BLOWN FLAPS, JET IMPINGEMENT, OBLIQUE WINGS,...
The downshear reformation of Tropical Storm Gabrielle (2001) was investigated using radar reflectivity and lightning data that were nearly continuous in time, as well as frequent aircraft reconnaissance flights. Initially the storm was a marginal tropical storm in an environment with strong 850-200 hPa vertical wind shear of 12-13 meters per second and an approaching upper tropospheric trough. Both the observed outflow and an adiabatic balance model calculation showed that the radial-vertical...
Topics: NASA Technical Reports Server (NTRS), CYCLONES, TROPICAL STORMS, MESOSCALE PHENOMENA, CONVECTION,...
Journal of Research of the National Bureau of Standards
Topics: buoyant convection, finite difference computations, fire-enclosure, fluid flow, Lanczos smoothing,...
286
286
Jul 26, 2010
07/10
by
Clement, Warren F.; Gorder, Peter J.; Jewell, Wayne F
texts
eye 286
favorite 0
comment 0
Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE (ANOE) navigation and flight control. Innovative guidance and control concepts are investigated in a four-fold research effort that: (1) organizes the on-board computer-based storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan; (2) defines a class of automatic anticipative pursuit guidance algorithms and...
Topics: ATMOSPHERIC MODELS, VORTICITY, STATISTICAL ANALYSIS, STORMS, THUNDERSTORMS, TORNADOES, ANVIL...
210
210
Jul 11, 2010
07/10
by
Low, C. A., Jr
texts
eye 210
favorite 0
comment 0
The major objective was to define the exact role of an onboard spacecraft computer in the control of ion thrusters. An initial computer control system with accurate high speed capability was designed, programmed, and tested with the computer as the sole control element for an operating ion thruster. The command functions and a code format for a spacecraft digital control system were established. A second computer control system was constructed to operate with these functions and format. A...
Topics: FLOW CHARACTERISTICS, JET IMPINGEMENT, NOISE PROPAGATION, COMPUTER PROGRAMMING, FLOW DISTRIBUTION,...
166
166
May 23, 2011
05/11
by
Hakkila, Jo
texts
eye 166
favorite 0
comment 0
The investigative team for the CCRO Cycle 5 Guest Investigation 'Gamma-Ray Burst Model Constraints Imposed by Burst and Transient Source Experiment (BATSE) Observations' consisted of myself, Dr. Charles A. Meegan (NASA/MSFC), Dr. Geoffrey N. Pendleton (UAH), Dr. John M. Horack (NASA/MSFC), and Dr. Michael S. Briggs (UAH). The purpose of the research was to continue studying the BATSE gamma-ray burst angular and intensity distributions in order to better determine the gamma-ray burst distance...
Topics: AEROACOUSTICS, MATRICES (MATHEMATICS), SOUND WAVES, BOUNDARY CONDITIONS, FINITE DIFFERENCE THEORY,...
A synoptic investigation employing quasi-Lagrangian diagnostic techniques was conducted for a North Atlantic Ocean polar flow undergoing a period or rapid cyclogenesis. The polar flow was of relatively small horizontal scale and developed in a region of low static stability and large low-level baroclinity, which is consistent with theoretical studies. Rapid surface pressure falls and vigorous circulation increases correlate well with the observed maxima in low-level inward mass transport and...
Topics: Meteorology, Maritime, North Atlantic, Quasi-Langrangian diagnostics, Mass budget, Stability...
A new model dissipation rate equation is proposed based on the dynamic equation of the mean-square vorticity fluctuation for large Reynolds number turbulence. The advantage of working with the vorticity fluctuation equation is that the physical meanings of the terms in this equation are more clear than those in the dissipation rate equation. Hence, the model development based on the vorticity fluctuation equation is more straightforward. The resulting form of the model equation is consistent...
Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYERS, CHANNEL FLOW, EDDY VISCOSITY, SEPARATED...
567
567
May 31, 2011
05/11
by
Mukkamala, Rav
texts
eye 567
favorite 0
comment 0
During the two-year project period, we have worked on several aspects of Health Usage and Monitoring Systems for structural health monitoring. In particular, we have made contributions in the following areas. 1. Reference HUMS architecture: We developed a high-level architecture for health monitoring and usage systems (HUMS). The proposed reference architecture is shown. It is compatible with the Generic Open Architecture (GOA) proposed as a standard for avionics systems. 2. HUMS kernel: One of...
Topics: AIR JETS, MOMENTUM, FLUX DENSITY, CROSS FLOW, YAW, PITCH (INCLINATION), FLOW DISTRIBUTION,...
For DES, RANS is responsible for predicting boundary layer growth and separation. LES is responsible for predicting the geometry dependent turbulent flow features. Grid adaptation done using NASA Langley s RefineMesh program. Adaptation on time average of vorticity
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, AERODYNAMIC STALLING, TURBULENT...
The velocity field created by the wake of an airfoil undergoing a prescribed pitching motion was sampled using hot wire anemometry. Data analysis methods concerning resolution of velocity components from cross wire data, computation of vorticity from velocity time history data, and calculation of vortex circulation from vorticity field data are discussed. These data analysis methods are applied to a flow field relevant to a two dimensional blade-vortex interaction study. Velocity time history...
Topics: NASA Technical Reports Server (NTRS), AIRFOILS, PITCH (INCLINATION), VORTICES, VORTICITY, WAKES,...
The influence of convective activity on the vorticity budget was determined during the AVE VII and AVE-SESAME I periods. This was accomplished by evaluating each term in the expanded vorticity equation with twisting and tilting and friction representing the residual of all other terms. Convective areas were delineated by use of radar summary charts. The influence of convective activity was established by analyzing contoured fields of each term as well as numerical values and profiles of the...
Topics: NASA Technical Reports Server (NTRS), CONVECTION, FRICTION, VORTICITY, COMPUTER PROGRAMS, CYCLONES,...
162
162
Jun 12, 2011
06/11
by
Palumbo, Dan; Chabalko, Chri
texts
eye 162
favorite 0
comment 0
Persistent structures in the turbulent boundary layer are located and analyzed. The data are taken from flight experiments on large commercial aircraft. An interval correlation technique is introduced which is able to locate the structures. The Morlet continuous wavelet is shown to not only locates persistent structures but has the added benefit that the pressure data are decomposed in time and frequency. To better understand how power is apportioned among these structures, a discrete Coiflet...
Topics: THREE DIMENSIONAL FLOW, SIMULATION, EIGENVALUES, JET FLOW, MATHEMATICAL MODELS, ASPECT RATIO,...
The feasibility of a general theory for the time-domain unsteady aerodynamics of helicopter rotors is investigated. The wake theory gives a linearized relation between the downwash and the wing bound circulation, in terms of the impulse response obtained directly in the time domain. This approach makes it possible to treat general wake configurations, including discrete wake vorticity with rolled-up and distorted geometry. The investigation establishes the approach for model order reduction;...
Topics: NASA Technical Reports Server (NTRS), AEROELASTICITY, ROTARY WINGS, ROTORS, UNSTEADY AERODYNAMICS,...
400
400
May 28, 2011
05/11
by
Sanchez, Merri J
texts
eye 400
favorite 0
comment 0
This project aimed to develop a methodology for evaluating performance and acceptability characteristics of the pressurized crew module volume suitability for zero-gravity (g) ingress of a spacecraft and to evaluate the operational acceptability of the NASA crew return vehicle (CRV) for zero-g ingress of astronaut crew, volume for crew tasks, and general crew module and seat layout. No standard or methodology has been established for evaluating volume acceptability in human spaceflight...
Topics: SHIELDING, HELMHOLTZ VORTICITY EQUATION, ACTIVE CONTROL, NOISE REDUCTION, CONTROL SURFACES,...
3,528
3.5K
Jul 12, 2010
07/10
by
Dillenius, M. F. E.; Nielsen, J. N
texts
eye 3,528
favorite 0
comment 0
Computer programs are presented which are capable of calculating detailed aerodynamic loadings and pressure distributions acting on pitched and rolled supersonic missile configurations which utilize bodies of circular or elliptical cross sections. The applicable range of angle of attack is up to 20 deg, and the Mach number range is 1.3 to about 2.5. Effects of body and fin vortices are included in the methods, as well as arbitrary deflections of canard or fin panels.
Topics: ATMOSPHERIC CIRCULATION, RECTANGLES, FLOW DISTRIBUTION, NUMERICAL FLOW VISUALIZATION, TURBULENT...
406
406
Jul 23, 2010
07/10
by
NON
texts
eye 406
favorite 0
comment 0
Topics addressed include: remote sensing; petrology; imaging spectroscopy; structural properties; thermal evolution; Earth mantle; early Earth; and megageomorphology.
Topics: DIFFUSION FLAMES, TURBULENCE MODELS, VORTICITY, FLAME PROPAGATION, MIXING LAYERS (FLUIDS), SCALARS,...
Viscous, axisymmetric vortex rings are investigated numerically by solving the incompressible Navier-Stokes equations using a spectral method designed for this type of flow. The results presented are axisymmetric, but the method is developed to be naturally extended to three dimensions. The spectral method relies on divergence-free basis functions. The basis functions are formed in spherical coordinates using Vector Spherical Harmonics in the angular directions, and Jacobi polynomials together...
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, NAVIER-STOKES EQUATION,...
The standard point vortex method has recently been shown to be of high order of accuracy for problems on the whole plane, when using a uniform initial subdivision for assigning the vorticity to the points. If obstacles are present in the flow, this high order deteriorates to first or second order. New vortex methods are introduced which are of arbitrary accuracy (under regularity assumptions) regardless of the presence of bodies and the uniformity of the initial subdivision.
Topics: NASA Technical Reports Server (NTRS), PARTICLE THEORY, POINTS (MATHEMATICS), VORTICITY EQUATIONS,...
170
170
Jul 25, 2010
07/10
by
Penzo, Paul A
texts
eye 170
favorite 0
comment 0
For experimentation, space offers an environment which is unobtainable on earth. One characteristic is a gravity force less than 1 g, where g is the mean earth gravity acceleration of 9.8 m/sq s. The production of uniform gravity levels above zero g in space is discussed in relationship to experimental needs. For planetology experiments, providing gravity in space will make it possible to more nearly simulate conditions on natural bodies. The g-level is but one parameter involved in the design...
Topics: ANTARCTIC REGIONS, SATURATION, TEMPERATURE MEASUREMENT, U-2 AIRCRAFT, VORTICITY, DEHYDRATION,...
318
318
Jul 23, 2010
07/10
by
Wie, Bong; Anthony, Tobi
texts
eye 318
favorite 0
comment 0
The major objective of this project is to develop a computer-aided approach to nonlinear stability analysis and nonlinear control system design. This goal is to be obtained by refining the describing function method as a synthesis tool for nonlinear control design. The interim report outlines the approach by this study to meet these goals including an introduction to the INteractive Controls Analysis (INCA) program which was instrumental in meeting these study objectives. A single-input...
Topics: METEOROLOGICAL CHARTS, VORTICITY, OZONE DEPLETION, SOUTHERN HEMISPHERE, STRATOSPHERE, ATMOSPHERIC...
