| Computational Fluid Dynamics Studies of a Flapping Wing Nano Air Vehicle (NAV) |
31-Dec-2008 |
51 pages |
| Authors:
Ravi Ramamurti; Jason Geder; William C Sandberg; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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 | The goal of this project is to develop a Nano Air Vehicle (NAV) with a wing span of 7.5 cm. The computational fluid dynamics study is focused on the aerodynamic efficiency of the wings. The primary focus of the computational study is on the aerodynamic performance of the wings in order to obtain a near optimal kinematics of the wing while the NAV is in a hover mode. The secondary ... |
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| Regular and Mach Reflections to Mach 18 with Air and TNT Detonation Products |
10-Sep-2008 |
15 pages |
| Authors:
Douglas Schwer; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| This report describes the computation of critical incident shock wave angles for regular (alpha sub d) reflections as a function of Mach number up to 18. First, the effect of different values for the specific heat ratio (gamma) is examined, and is found that as gamma decreases from 1.4 to 1.2, the value for alpha sub N decreases for regular reflections, and the value for alpha sub d increases, resulting ... |
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| Computations of Chaotic Flows in Micromixers |
07 APR 2006 |
39 pages |
| Authors:
Carolyn R. Kaplan; Junhui Liu; David R. Mott; Elaine S. Oran; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| Three-dimensional simulations of the incompressible Navier-Stokes equations are used to examine the effects of repeating sequences of herringbone ridges in a microchannel. The calculations show how the presence of the structures leads to an asymmetrical pattern of transverse vortices in the velocity field, how this pattern repeats as the fluid moves over each similar sequence of ridges, how this velocity field stretches and folds fluid elements, and how this can ... |
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| Design of Nozzle for UV Fluorescence Detector |
17 MAY 2001 |
27 pages |
| Authors:
Ravi Ramamurti; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| The flow through the nozzle of a Ultra-Violet (UV) Fluorescence detector is computed. The primary goal of this project is to study the flow exiting the nozzle and predict the spreading of the flow at a specified distance from the exit of the nozzle. The unstructured mesh-based incompressible flow solver, FEFLO, is used to compute this flow. Computed pressure drops across the nozzle are compared with experiment and shows good ... |
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| Advanced Simulation Tool for Improved Damage Assessment 2) Water-Mist Suppression of Large Scale Compartment Fires |
29 DEC 2000 |
27 pages |
| Authors:
Kuldeep Prasad; Gopal Patnaik; K. Kailasanath; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| This report is the second in a series that discusses the development of an advanced simulation tool for improved damage assessment. In the first report, we adopted a domain decomposition approach, based on the multiblock Chimera technique, to simulate fires in single uncluttered compartments and predicted spread of smoke in multi compartment ship geometries. These simulations demonstrated the capability of the tool to simulate complex flow fields in large multi ... |
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| Advanced Simulation Tool for Improved Damage Assessment. 1) A MultiblockTechnique for Simulating Fire and Smoke Spread in Large Complex Enclosures |
21 FEB 2000 |
31 pages |
| Authors:
Kuldeep Prasad; Gopal Patnaik; K. Kailasanath; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| Several recent developments in computational techniques have been combined to develop a tool for simulating the reactive flow field inside large complex enclosures. The multiblock technique was adopted to solve the unsteady compressible Navier Stokes equations inside a large fire compartment. Numerical simulations of a 330 kW and a 980 kW fire in a single uncluttered compartment have been performed. Peak ceiling jet temperature of ... |
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| Numerical Modeling of Fire Suppression Using Water Mist. 4. Suppression of Liquid Methanol Pool Fires |
03 DEC 1998 |
27 pages |
| Authors:
Kuldeep Prasad; Chiping Li; K. Kailasanath; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| This report is the fourth in a series dealing with numerical modeling of fire suppression using water mist. While the first two reports examined the interaction of water mist with two-dimensional methane air diffusion flames, the third report presented a numerical model for studying methanol liquid pool fires, As shown in that report, numerical results exhibited a flame structure that compared well with experimental observations and thermocouple temperature measurements. In ... |
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| Numerical Modeling of Fire Suppression Using Water Mist. 3. Methanol Liquid Pool Fire Model |
30 OCT 1998 |
37 pages |
| Authors:
Kuldeep Prasad; Chiping Li; K. Kailasanath; Chuka Ndubizu; Ramagopal Ananth; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| This report is the third in a series dealing with the numerical modeling of fire suppression using water mist. In the first report, a numerical study was described for obtaining a detail understanding of the physical processes involved during the interaction of water-mist and methane-air diffusion flames. The relative contribution of the various Suppression mechanisms was studied and detailed comparison with experimental results was ... |
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| Numerical Modeling of Fire Suppression Using Water Mist. 2. An Optimization Study on Jet Diffusion Flames |
22 JUN 1998 |
27 pages |
| Authors:
K. Prasad; C. Li; K. Kailasanath; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| This report is the second in a series that discusses the numerical modeling of fire suppression using water-mist. In the first report, a numerical study was described for obtaining a detail understanding of the physical processes involved during the interaction of water-mist and flames. The relative contribution of the various suppression mechanisms for methane-air diffusion flames was studied and detailed comparison with experimental results was provided in the first report. ... |
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| Numerical Modeling of Fire Suppression Using Water Mist. 1. Gaseous Methane-Air Diffusion Flames |
19 JAN 98 |
52 pages |
| Authors:
K. Prasad; C. Li; K. Kailasanath; C. Ndubizu; R. Ananth; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| This report is the first in a series dealing with the numerical modeling of fire suppression using water mist. The focus of this report is on the suppression of gas jet diffusion flames using fine water droplets. A two continuum formulation is used in which the gas phase and the water mist are both described by equations of the eulerian form. The model is used to obtain a detail understanding ... |
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| Computation of the 3-D Unsteady Flow Past Deforming Geometries |
20 OCT 97 |
24 pages |
| Authors:
Ravi Ramamurti; William C. Sandberg; Rainald Lohner; NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR REACTIVE FLOW AND DYNAMICAL SYSTEMS
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| A 3-D incompressible unsteady flow solver based on simple finite elements with adaptive remeshing and grid movement for both moving and deforming surfaces is described. We demonstrate the combination of adaptive remeshing technique with the incompressible flow solver by computing the flow past an undulating eel in 2-D and past a swimming bluefin tuna in 3-D. It is clear that proper choice of the amplitude and frequency of undulation is ... |
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Reports by Corporate Author
