Wind Flow Simulation Around NASA KSC Vehicle Assembly Building

2004 ◽  
Author(s):  
B. T. Vu ◽  
M. J. Verdier
Keyword(s):  
Flow Field ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Wind Flow ◽  
Flow Solver ◽  
Wind Speeds ◽  
Velocity Magnitude ◽  
Operations And Maintenance ◽  
Kennedy Space ◽  
Detailed Mathematical Analysis

A model of the wind flow conditions around Kennedy Space Center (KSC) Vehicle Assembly Building (VAB) is presented. An incompressible Navier-Stokes flow solver was used to compute the flow field around fixed Launch Complex 39 (LC-39) buildings and structures. The 3-D flow field, including velocity magnitude and velocity vectors, was established to simulate the localized wind speeds and directions at specified locations in and around LC-39 buildings and structures. The results of this study not only help explain the physical phenomena of the flow patterns around LC-39 buildings but also are useful to the Shuttle personnel. Current Operations and Maintenance Requirements and Specifications (OMRS) for vehicle transfer operations are based on empirically derived historical data, and no detailed mathematical analysis of wind conditions around LC-39 structures has ever been accomplished.

Analysis of the Unsteady Flow in an Aspirated Counter-Rotating Compressor Using the Nonlinear Harmonic Method

2009 ◽  
Author(s):  
Emanuele Guidotti ◽  
Mark G. Turner
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Frequency Domain ◽  
Navier Stokes ◽  
Test Case ◽  
Numerical Accuracy ◽  
Flow Solver ◽  
Harmonic Method ◽  
Flow Change ◽  
Inlet Boundary Condition

A multistage frequency domain (Nonlinear Harmonic) Navier-Stokes unsteady flow solver has been used to analyze the flow field in the MIT (rotor/rotor) aspirated counter-rotating compressor. The numerical accuracy and computational efficiency of the Nonlinear Harmonic method implemented in Numeca’s Fine/Turbo CFD code has been demonstrated by comparing predictions with experimental data and nonlinear time-accurate solutions for the test case. The comparison is good, especially considering the big savings in time with respect to a time accurate simulation. An imposed inlet boundary condition takes into account the flow change due to the IGV (not simulated in the computational model). Details of the flow field are presented and physical explanations are provided. Also, suggestions and recommendations on the use of the Nonlinear Harmonic method are provided. From this work it can be concluded that the development of efficient frequency domain approaches enables routine unsteady flow predictions to be used in the design of modern turbomachinery.

Analysis of Complex Three-Dimensional Flow in a Three-Stage LP Turbine by Means of Transitional Navier-Stokes Simulation

2000 ◽  
Author(s):  
Jochen Gier ◽  
Sabine Ardey ◽  
Adam Heisler
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Flow Visualisation ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Lp Turbine ◽  
Extensive Experimental Data ◽  
Highly Loaded

The complex three-dimensional flow field in a highly loaded three-stage LPT is analysed on the basis of a steady three-dimensional flow simulation. The quality of the simulation concerning this configuration is demonstrated by means of a comparison with extensive experimental data gathered in a turbine test rig. For an accurate representation of the transitional character of the turbine flow a modified version of the Abu-Ghannam Shaw transition model is employed in the TRACE_S Navier-Stokes code in connection with a two-equation turbulence model. The flow field of this highly loaded turbine is characterised by complex secondary flow pattern as well as local separation and reattachment zones. The need and applicability of transition modelling is demonstrated by a comparison with a fully turbulent calculation and experimental flow visualisation. The basic flow structure is described in terms of several characteristic quantities and discussed in detail. For further analysis variations of the point of operation and the geometry also based on experiments are included in this investigation.

Numerical Simulations of Wind Effects on an Array of Ground Mounted Solar Panels

2014 ◽  
Author(s):  
Chowdhury Jubayer ◽  
Horia Hangan
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Numerical Simulations ◽  
Solar Panel ◽  
Navier Stokes ◽  
Wind Flow ◽  
Solar Panels ◽  
Array Configuration ◽  
Piv Measurement ◽  
Overturning Moment

In this study, numerical simulations using unsteady Reynolds-Averaged Navier-Stokes (RANS) approach with Shear Stress Transport (SST) k-ω turbulence closure are employed to investigate the wind loads and wind flow field of a ground mounted solar panel array. Atmospheric boundary layer wind profiles for open terrain roughness with Reynolds number of 2.2×106, based on the wind speed at the lower edge and the chord length of a stand-alone system, are employed. Four different wind directions (0°, 45°, 135° and 180°) are considered. The numerical modeling approach employed in this study is validated for a stand-alone solar panel system by comparing the surface pressures with the study by [1] and the velocity field with a Particle Image Velocimetry (PIV) measurement carried out in the Boundary Layer Wind Tunnel I at the Western University, Canada. Analyzing the wind flow field for the array configuration shows that for 0° and 180° wind directions, all trailing rows are in the complete wake of the first windward row. It is also shown that in terms of maximum drag and lift, 0° and 180° wind directions are the critical wind directions with the first windward row being the critical row. On the other hand, in terms of overturning moment, 45° and 135° are the critical wind directions, with similar overturning moment coefficients for each row.

On a New Model Reduction Method for CFD Systems Used for Flow Control Design

2013 ◽  
Vol 332 ◽  
pp. 9-14
Author(s):  
Adrian Mihail Stoica ◽  
Marius Stoia-Djeska
Keyword(s):  
Model Reduction ◽  
Flow Simulation ◽  
Type Systems ◽  
Discrete Systems ◽  
Navier Stokes ◽  
Governing Equations ◽  
Flow Solver ◽  
Efficient Control ◽  
Flow Domain ◽  
External Flows

The use of active control to get better characteristics of unsteady internal and external flows is the ultimate goal of the research presented in this paper. Usually, unsteady flows are calculated using Euler and/or Navier-Stokes solvers. The efficiency of numerical simulation of an unsteady flow dramatically increases if the unsteady solution is a small perturbation about a steady-state flow, due to disturbances occurring at the boundaries of the flow domain. The main difficulty related to the flow simulation is that any CFD (Computational Fluid Dynamics) technique generates discrete systems with a very large number of states. In order to design an efficient control, the flow solver must be not only accurate and numerically effective, but also it must have a low number of states. The aim of this paper is to present a new method for model reduction of CFD systems using representative governing equations. The focus is on descriptor type systems resulting from the spatial discretization of the CFD governing equations.

scholarly journals GPU IMPLEMENTATION OF A VISCOUS FLOW SOLVER ON UNSTRUCTURED GRIDS

2016 ◽  
Vol 42 ◽  
pp. 1660167
Author(s):  
TIANHAO XU ◽  
LONG CHEN
Keyword(s):  
Graphics Processing Units ◽  
Stokes Equations ◽  
Unstructured Grids ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Competitive Advantages ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Volume Method ◽  
Graphics Processing

Graphics processing units have gained popularities in scientific computing over past several years due to their outstanding parallel computing capability. Computational fluid dynamics applications involve large amounts of calculations, therefore a latest GPU card is preferable of which the peak computing performance and memory bandwidth are much better than a contemporary high-end CPU. We herein focus on the detailed implementation of our GPU targeting Reynolds-averaged Navier-Stokes equations solver based on finite-volume method. The solver employs a vertex-centered scheme on unstructured grids for the sake of being capable of handling complex topologies. Multiple optimizations are carried out to improve the memory accessing performance and kernel utilization. Both steady and unsteady flow simulation cases are carried out using explicit Runge-Kutta scheme. The solver with GPU acceleration in this paper is demonstrated to have competitive advantages over the CPU targeting one.

scholarly journals Assessment of Two-Equation Turbulence Models and Validation of the Performance Characteristics of an Experimental Wind Turbine by CFD

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Ece Sagol ◽  
Marcelo Reggio ◽  
Adrian Ilinca
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Wind Turbine ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Bending Moment ◽  
Mesh Size ◽  
Turbine Rotor ◽  
Cross Sectional ◽  
Wind Speeds

The very first step in the simulation of ice accretion on a wind turbine blade is the accurate prediction of the flow field around it and the performance of the turbine rotor. The paper addresses this prediction using RANS equations with a proper turbulence model. The numerical computation is performed using a commercial CFD code, and the results are validated using experimental data for the 3D flow field around the NREL Phase VI HAWT rotor. For the flow simulation, a rotating reference frame method, which calculates the flow properties as time-averaged quantities, has been used to reduce the time spent on the analysis. A basic grid convergence study is carried out to select the adequate mesh size. The two-equation turbulence models available in ANSYS FLUENT are compared for a 7 m/s wind speed, and the one that best represents the flow features is then used to determine moments on the turbine rotor at five wind speeds (7 m/s, 10 m/s, 15 m/s, 20 m/s, and 25 m/s). The results are validated against experimental data, in terms of shaft torque, bending moment, and pressure coefficients at certain spanwise locations. Streamlines over the cross-sectional airfoils have also been provided for the stall speed to illustrate the separation locations. In general, results have shown good agreement with the experimental data for prestall speeds.

Aerodynamic Characterisation of Ramjet Missile through Combined External-internal Computational Fluid Dynamics Simulation

2016 ◽  
Vol 66 (6) ◽  
pp. 624 ◽  
Author(s):  
Anand Bhandarkar ◽  
Souraseni Basu ◽  
P. Manna ◽  
Debasis Chakraborty
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Internal Flow ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Navier Stokes Equations

<p>Combined external-internal flow simulation is required for the estimation of aerodynamic forces and moments of high speed air-breathing vehicle design. A wingless, X-tail configuration with asymmetrically placed rectangular air intake is numerically explored for which experimental data is available for different angles of attack. The asymmetrically placed air intakes and protrusions make the flow field highly three-dimensional and existing empirical relations are inadequate for preliminary design. Three dimensional Navier Stokes equations along with SST-kω turbulence model were solved with a commercial CFD solver to analyse the combined external and internal flow field of the configuration at different angles of attack. Estimated aerodynamic coefficients match well with experimental data and estimated drag coefficient are within 8.5 per cent of experimental data. Intake performance parameters were also evaluated for different angles of attack.</p>

Navier-Stokes Simulation of Air-Conditioning Facility of a Large Modern Computer Room

2005 ◽  
Author(s):  
Jasim U. Ahmad ◽  
Shishir A. Pandya ◽  
William M. Chan ◽  
Neal M. Chaderjian
Keyword(s):  
Air Conditioning ◽  
Large Scale ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Flow Solver ◽  
Low Mach Number ◽  
Geometry Modeling ◽  
Modern Computer ◽  
Nasa Ames Research ◽  
Viscous Compressible Flow

A 3-D full Navier-Stokes simulation of a large scale computing facility at NASA Ames Research center was carried out to assess the adequacy of the existing air handling and conditioning system. The flow simulation of this modern facility was modeled with a viscous, compressible flow solver code OVERFLOW-2 with low Mach number pre-conditioning. A script was created to automate geometry modeling, grid generation, and flow solver input preparation. A new set of air-conditioning boundary conditions was developed and added to the flow solver. Detailed flow visualization was performed to show temperature distribution, air-flow streamlines and velocities in the computer room.

scholarly journals Velocity Flow Field Characteristic on Nozzle Cavity using Central Composite Design of Computational Method for Dry Ice Blasting System

2021 ◽  
Vol 2129 (1) ◽  
pp. 012020
Author(s):  
Mohamad Nur Hidayat Mat ◽  
Md Faisal Md Basir ◽  
Mohamad Farid Sies
Keyword(s):  
Flow Field ◽  
Computational Method ◽  
Nozzle Geometry ◽  
Navier Stokes ◽  
Flow Area ◽  
Ansys Fluent ◽  
Dry Ice ◽  
Velocity Magnitude ◽  
Velocity Flow ◽  
Dry Ice Blasting

Abstract In the development of dry ice blasting nozzle geometry, the critical process parameters depend on particle jet velocity. However, very few researchers have attempted sensitivity on the velocity flow area of specific nozzle geometric parameters. A numerical simulation approach was performed in this paper using Ansys Fluent to investigate different nozzle parameters on the velocity flow field. A two-dimensional model is solved iteratively using averaged Navier-Stokes under Eulerian flow description. It was found that the velocity value increases that reach 550 m/s with an increment of the nozzle area ratio of up to 20 without influencing convergent angle and the velocity magnitude drop linearly from 525 m/s to 505 m/s in with the rise of divergent length that swell up to 700 mm and with constant convergent angle and convergent length.

Numerical Transonic Flow Field Predictions for NASA Compressor Rotor 37

1995 ◽  
Author(s):  
Peter Dalbert ◽  
Donald H. Wiss
Keyword(s):  
Flow Field ◽  
Axial Compressor ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Nasa Lewis Research ◽  
Solution Strategies ◽  
Compressor Rotor ◽  
High Prediction ◽  
Computer Resources

Flow field calculations of the NASA transonic axial compressor Rotor 37 are presented. These were obtained by the two commercially available 3D Navier Stokes-codes BTOB3D and TASCflow using different turbulence models, i.e. Baldwin-Lomax and k-ε. Some of the results were submitted to the CFD code assessment exercise organized in 1994 by the Turbomachinery Committee of the ASME, where a number of “blind” CFD predictions were compared against previously unknown experimental data taken at the NASA Lewis Research Center. The objective of these calculations was to use the codes in the same way as they are generally used by experienced engineers for standard industrial design tasks. Thus, the effort involved in grid generation, flow simulation runs and postprocessing was subject to the usual limitations in computer resources as well as a stringent observation of cost-effectiveness (manpower and time available). With both codes, two sets of calculations were carried out: BTOB3D with two different tip clearances and TASCflow with a uniform and a spanwise varying outlet static pressure. Generally, the results of both codes show good agreement with respect to the measured overall performance characteristics and averaged spanwise distributions. In particular, the TASCflow solutions display high prediction accuracy in some local details of the flow field while in the BTOB3D code, boundary effects seem to mix out the flow significantly. The solution strategies employed as well as the reasons for certain discrepancies between computations and measurements are discussed.

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