Using Computational Fluid Dynamics Rigid Body Dynamic Cfd Rbd Results To Generate Aerodynamic Models For Projectile Flight Simulation

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Using Computational Fluid Dynamics Rigid Body Dynamic Cfd Rbd Results To Generate Aerodynamic Models For Projectile Flight Simulation
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Author : Mark Costello
language : en
Publisher:
Release Date : 2007
Using Computational Fluid Dynamics Rigid Body Dynamic Cfd Rbd Results To Generate Aerodynamic Models For Projectile Flight Simulation written by Mark Costello and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Airplanes categories.
"A method to efficiently generate a complete aerodynamic description for projectile flight dynamic modeling is described. At the core of the method is an unsteady, time-accurate computational fluid dynamics simulation that is tightly coupled to a rigid projectile flight dynamic simulation. A set of short time snippets of simulated projectile motion at different Mach numbers is computed and employed as baseline data. For each time snippet, aerodynamic forces and moments and the full rigid body state vector of the projectile are known. With time-synchronized air loads and state vector information, aerodynamic coefficients can be estimated with a simple fitting procedure. By inspecting the condition number of the fitting matrix, we can assess the suitability of the time history data to predict a selected set of aerodynamic coefficients. The technique is exercised on an exemplar fin-stabilized projectile with good results."--Report documentation page.
Using Computational Fluid Dynamics Rigid Body Dynamic Cfd Rbd Results To Generate Aerodynamic Models For Projectile Flight Simulation
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Author : Mark Costello
language : en
Publisher:
Release Date : 2007
Using Computational Fluid Dynamics Rigid Body Dynamic Cfd Rbd Results To Generate Aerodynamic Models For Projectile Flight Simulation written by Mark Costello and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Airplanes categories.
"A method to efficiently generate a complete aerodynamic description for projectile flight dynamic modeling is described. At the core of the method is an unsteady, time-accurate computational fluid dynamics simulation that is tightly coupled to a rigid projectile flight dynamic simulation. A set of short time snippets of simulated projectile motion at different Mach numbers is computed and employed as baseline data. For each time snippet, aerodynamic forces and moments and the full rigid body state vector of the projectile are known. With time-synchronized air loads and state vector information, aerodynamic coefficients can be estimated with a simple fitting procedure. By inspecting the condition number of the fitting matrix, we can assess the suitability of the time history data to predict a selected set of aerodynamic coefficients. The technique is exercised on an exemplar fin-stabilized projectile with good results."--Report documentation page.
Computational Ballistics Iii
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Author : C. A. Brebbia
language : en
Publisher: WIT Press
Release Date : 2007
Computational Ballistics Iii written by C. A. Brebbia and has been published by WIT Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Technology & Engineering categories.
Containing the proceedings of the Third International Conference on Computational Ballistics, this book presents new ideas and advanced developments in the field of study of Computational Ballistics. Ballistic studies include applications as varied as the study of the structural and control behavior of rockets and communication satellites; bird strike effects on commercial aircraft, terrorist attacks and automobile crack worthiness modelling. Many basic problems of ballistics are similar to those in other fields of applications, such as combustion, heat conduction, in-flight structural behaviour, trajectory related issues, contact, impact, penetration, structural response to shock waves and many others.A valuable contribution to its field, this text will be of interest to researchers involved in the different areas of computational ballistics and their relationship between computational methods and experiments. Notable topics include: Systems and Technolog; Combustion and Heat Transfer; Propellants; Fluid Dynamics; Fluid Flow and Aerodynamics; In-Flight Structural Behaviour and Material Response; Guidance and Control; Perforation and Penetration Mechanics; Fluid-structure Interaction; Experimental Mechanics/ballistic and Field Testing; High Rate Loads; Composite Material; Shock and Impact.
Generating An Aerodynamic Model For Projectile Flight Simulation Using Unsteady Time Accurate Computational Fluid Dynamic Results
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Author :
language : en
Publisher:
Release Date : 2006
Generating An Aerodynamic Model For Projectile Flight Simulation Using Unsteady Time Accurate Computational Fluid Dynamic Results written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
A method to efficiently generate a complete aerodynamic description for projectile flight dynamic modeling is described. At the core of the method is an unsteady, time accurate computational fluid dynamics simulation that is tightly coupled to a rigid body dynamics simulation. A set of n short time snippets of simulated projectile motion at m different Mach numbers is computed and employed as baseline data. For each time snippet, aerodynamic forces and moments and the full rigid body state vector of the projectile are known. With time synchronized air loads and state vector information, aerodynamic coefficients can be estimated with a simple fitting procedure. By inspecting the condition number of the fitting matrix, it is straightforward to assess the suitability of the time history data to predict a selected set of aerodynamic coefficients. To highlight the merits of this technique, it is exercised on example data for a fin-stabilized projectile. The technique is further exercised for a fin- and spin-stabilized projectile using simulated data from a standard trajectory code.
Computational Aerodynamic Modeling Of Aerospace Vehicles
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Author : Mehdi Ghoreyshi
language : en
Publisher: MDPI
Release Date : 2019-03-08
Computational Aerodynamic Modeling Of Aerospace Vehicles written by Mehdi Ghoreyshi and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-03-08 with Technology & Engineering categories.
Currently, the use of computational fluid dynamics (CFD) solutions is considered as the state-of-the-art in the modeling of unsteady nonlinear flow physics and offers an early and improved understanding of air vehicle aerodynamics and stability and control characteristics. This Special Issue covers recent computational efforts on simulation of aerospace vehicles including fighter aircraft, rotorcraft, propeller driven vehicles, unmanned vehicle, projectiles, and air drop configurations. The complex flow physics of these configurations pose significant challenges in CFD modeling. Some of these challenges include prediction of vortical flows and shock waves, rapid maneuvering aircraft with fast moving control surfaces, and interactions between propellers and wing, fluid and structure, boundary layer and shock waves. Additional topic of interest in this Special Issue is the use of CFD tools in aircraft design and flight mechanics. The problem with these applications is the computational cost involved, particularly if this is viewed as a brute-force calculation of vehicle’s aerodynamics through its flight envelope. To make progress in routinely using of CFD in aircraft design, methods based on sampling, model updating and system identification should be considered.
Unsteady Flow Computations Of A Finned Body In Supersonic Flight
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Author :
language : en
Publisher:
Release Date : 2007
Unsteady Flow Computations Of A Finned Body In Supersonic Flight written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
This report describes a multidisciplinary computational study undertaken to compute the flight trajectories and simultaneously predict the unsteady free flight aerodynamics of a finned projectile at supersonic speeds with the use of an advanced unstructured time-accurate Navier-Stokes computational technique. Actual flight trajectories are computed with an advanced coupled computational fluid dynamics (CFD)-rigid body dynamics (RBD) technique. In addition, our goal is to be able to extract the aerodynamic coefficients from these fully coupled time-accurate CFD-RBD computations. Computed positions and orientations of the projectile have been compared with actual data measured from free flight tests and are found to be generally in good agreement. Unsteady numerical results obtained from the coupled method and unstructured grids show the flow field, the extracted aerodynamic forces and moments, and the flight trajectories of the projectile. Aerodynamic coefficients such as the dynamic derivatives have been obtained with a separate unsteady time-accurate CFD approach and have been compared with the extracted aerodynamic coefficients from the fully coupled dynamic simulations.
On The Calculation Of Dynamic Derivatives Using Computational Fluid Dynamics
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Author : Andrea Da Ronch
language : en
Publisher:
Release Date : 2012
On The Calculation Of Dynamic Derivatives Using Computational Fluid Dynamics written by Andrea Da Ronch and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
In this thesis, the exploitation of computational fluid dynamics (CFD) methods for the flight dynamics of manoeuvring aircraft is investigated. It is demonstrated that CFD can now be used in a reasonably routine fashion to generate stability and control databases. Different strategies to create CFD-derived simulation models across the flight envelope are explored, ranging from combined low-fidelity/high-fidelity methods to reduced-order modelling. For the representation of the unsteady aerodynamic loads, a model based on aerodynamic derivatives is considered. Static contributions are obtained from steady-state CFD calculations in a routine manner. To more fully account for the aircraft motion, dynamic derivatives are used to update the steady-state predictions with additional contributions. These terms are extracted from small-amplitude oscillatory tests. The numerical simulation of the flow around a moving airframe for the prediction of dynamic derivatives is a computationally expensive task. Results presented are in good agreement with available experimental data for complex geometries. A generic fighter configuration and a transonic cruiser wind tunnel model are the test cases. In the presence of aerodynamic non-linearities, dynamic derivatives exhibit significant dependency on flow and motion parameters, which cannot be reconciled with the model formulation. An approach to evaluate the sensitivity of the non-linear flight simulation model to variations in dynamic derivatives is described. The use of reduced models, based on the manipulation of the full-order model to reduce the cost of calculations, is discussed for the fast prediction of dynamic derivatives. A linearized solution of the unsteady problem, with an attendant loss of generality, is inadequate for studies of flight dynamics because the aircraft may experience large excursions from the reference point. The harmonic balance technique, which approximates the flow solution in a Fourier series sense, retains a more general validity. The model truncation, resolving only a small subset of frequencies typically restricted to include one Fourier mode at the frequency at which dynamic derivatives are desired, provides accurate predictions over a range of two- and three-dimensional test cases. While retaining the high fidelity of the full-order model, the cost of calculations is a fraction of the cost for solving the original unsteady problem. An important consideration is the limitation of the conventional model based on aerodynamic derivatives when applied to conditions of practical interest (transonic speeds and high angles of attack). There is a definite need for models with more realism to be used in flight dynamics. To address this demand, various reduced models based on system-identification methods are investigated for a model case. A non-linear model based on aerodynamic derivatives, a multi-input discrete-time Volterra model, a surrogate-based recurrence-framework model, linear indicial functions and radial basis functions trained with neural networks are evaluated. For the flow conditions considered, predictions based on the conventional model are the least accurate. While requiring similar computational resources, improved predictions are achieved using the alternative models investigated. Furthermore, an approach for the automatic generation of aerodynamic tables using CFD is described. To efficiently reduce the number of high-fidelity (physics-based) analyses required, a kriging-based surrogate model is used. The framework is applied to a variety of test cases, and it is illustrated that the approach proposed can handle changes in aircraft geometry. The aerodynamic tables can also be used in real-time to fly the aircraft through the database. This is representative of the role played by CFD simulations and the potential impact that high-fidelity analyses might have to reduce overall costs and design cycle time.
Numerical Simulation Of Flat Plate Trajectory Using Coupled Cfd Rbd With Dynamic Meshing
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Author : Nidhi D. Sathyanarayana
language : en
Publisher:
Release Date : 2019
Numerical Simulation Of Flat Plate Trajectory Using Coupled Cfd Rbd With Dynamic Meshing written by Nidhi D. Sathyanarayana and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Electronic dissertations categories.
Foreign object debris including bird and/or drone strike debris upon impact, may cause critical secondary damage to downwind aircraft surfaces. This debris is simplified in geometry to a flat plate and represented as a rigid body for better comparison with experimental results. In this study, a coupled computational fluid dynamics (CFD)-rigid body dynamics (RBD) solver with dynamic meshing was used for numerical analysis of the flat plate trajectory in a uniform flow field. The computed trajectory of the rectangular flat plate was validated against available experimental data and compared with existing numerical results. Less than 10% difference was observed between the simulated trajectory and the experimental results. Furthermore, a parametric analysis and probability analysis were conducted to identify the sensitivity of plate trajectory to initial conditions and to obtain a probability distribution of the location of the center of gravity of the plate at a distance downstream of the release location. The studies depict the sensitivity of the path taken by the plate to initial release orientation and to initial angular velocities of the plate. Additionally, flow field interaction studies were conducted by simulating the release of multiple plates in the domain to observe the effect of distance and mass on the plate trajectories. Finally, a single plate was released in the vicinity of a wing for a qualitative analysis of the effect of change in aerodynamic forces on the plate trajectory due to the presence of the wing.
Application Of Computational Fluid Dynamics To A Monoplane Fixed Wing Missile With Elliptic Cross Sections
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Author : Karen R. Heavey
language : en
Publisher:
Release Date : 2005
Application Of Computational Fluid Dynamics To A Monoplane Fixed Wing Missile With Elliptic Cross Sections written by Karen R. Heavey and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Computational fluid dynamics categories.
This report describes a computational study undertaken to investigate the performance of the CFD++ flow solver for prediction of nonlinear aerodynamics of a complex finned missile using structured hexahedral and unstructured tetrahedral grids. A monoplane fixed-wing missile with elliptic cross sections provided a geometrically complex model. Numerical solutions were obtained for this configuration at supersonic speed for various roll orientations, angles of attack, and jaw angles. Steady-state solutions were obtained using a three-dimensional Reynolds-Averaged Navier-Stokes solver with a two-equation turbulence model. Numerical results show the qualitative features of the flow fields at various cross-sectional and streamwise positions along the computational model of the missile. Aerodynamic coefficients were extracted from the computed solutions and found to match well with the available experimental data for these configurations. These numerical results show the effectiveness of using computational fluid dynamics techniques to produce an accurate prediction of the aerodynamics of geometrically complete configurations.
Computational Fluid Dynamic Cfd Analysis Of A Generic Missile With Grid Fins
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Author : James DeSpirito
language : en
Publisher:
Release Date : 2000
Computational Fluid Dynamic Cfd Analysis Of A Generic Missile With Grid Fins written by James DeSpirito and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Computational fluid dynamics categories.
This report presents the results of a study demonstrating an approach for using viscous computational fluid dynamic simulations to calculate the flow field and aerodynamic coefficients for a missile with grid fin. A grid fin is an unconventional lifting and control surface that consists of an outer frame supporting an inner grid of intersecting planar surfaces of small chord. The calculations were made at a Mach number of 2.5 and several angles of attack for a missile without fins, with planar fms, and with grid fins. The results were validated by comparing the computed aerodynamic coefficients for the missile and individual grid fins against wind tunnel measurement data. Very good agreement with the measured data was observed for all configurations investigated. For the grid fin case, the aerodynamic coefficients were within 2.8-6.5% of the wind tunnel data. The normal force coefficients on the individual grid fins were within 11% of the test data. The simulations were also successful in calculating the flow structure around the fin in the separated-flow region at the higher angles of attack. This was evident in the successful calculation of the nonlinear behavior for that fin, which showed negative normal force at the higher angles of attack. The effective angle of attack is negative on either part of or all of the top grid fin for the higher angles of attack.