The progress made toward incorporating advanced, high-fidelity computational fluid dynamics (CFD) schemes into the VULCAN high-speed combustion simulation code is reported in this paper. The enhancements include bette...
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The progress made toward incorporating advanced, high-fidelity computational fluid dynamics (CFD) schemes into the VULCAN high-speed combustion simulation code is reported in this paper. The enhancements include better LES models, the capability to use high-order discretization schemes and the allowance for the simulation of combusting two-phase flows involving liquid fuel sprays. Regarding LES, we have successfully implemented, as baseline, Vreman's relatively high accurate approach and Menon's proposal, which involves the solution of an evolution equation for the sub-grid scale kinetic energy. Ideally, Vreman's formula can perform consistently without the need for any artificial wall-damping function, while Menon's LES model allows for non-equilibrium between sub-grid kinetic energy production and dissipation rates, and provides a natural measure of the sub-grid turbulence intensity. Several problems, both canonical and realistic, were used to validate the calculations. The results suggest the need to use high-order schemes to obtain accurate LES results. The baseline LES models were used in this exploratory work and advanced features such as the dynamic evaluation of several model constants, as in Genin and Menon (Genin, F. and Menon, S., "simulation of Turbulent Mixing Behind a Strut Injector in Supersonic Flow," aiaa Journal, Vol. 48, No. 3, pp. 526-539), are currently being added, subsequent to our basic understanding of the baseline schemes. Several high-order schemes based on the weighted essentially non-oscillatory (WENO) approach, some of which are new, were also implemented in VULCAN during this investigation and have been rigorously validated. Variants of the Sirignano (Sirignano, W.A., "Current status of spray combustion modeling," aiaa-2003-4784, 2003) two-phase models were used as the baseline for the two-phase flow implementation, with promising results for mixing and combustion in supersonic jet cross flow. However, the demonstration of two-phase fl
The proceedings contain 121 papers. The topics discussed include: performance measurements on the MPI stewart platform;Cal Poly's motion flight simulator and motion algorithms;piloted simulator evaluation of new f...
ISBN:
(纸本)9781563479458
The proceedings contain 121 papers. The topics discussed include: performance measurements on the MPI stewart platform;Cal Poly's motion flight simulator and motion algorithms;piloted simulator evaluation of new fault-tolerant flight control algorithms for reconstructed accident scenarios;development of a model-based safety analysis technique from the ETF flight simulator;airframe and trajectory pursuit modeling for simulation assisted air race planning;pilots' use of pitch and heave motion cues in a pitch control task;model verification and validation of a mobile robot system for 6-DOF motion emulation;evaluating an objective method for motion cueing fidelity;nonlinear ground dynamics of aircraft: bifurcation analysis of turning solutions;measuring and modeling neuromuscular system dynamics for haptic interface design;HORIZON 2.1: A space system simulation framework;and mobile robotic system for ground testing of multi-spacecraft proximity operations.
We present an adaptive flight control architecture that can augment an existing single or gain-scheduled linear controller. The approach is well suited for control of fixed-wing unmanned aerial vehicles which have alr...
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This paper presents a new helicopter transmission model in support of CBM initiatives. The model uses the first principles approach to analyze the rotating shafts and gear couplings using rotor dynamic analysis techni...
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ISBN:
(纸本)9781563479762
This paper presents a new helicopter transmission model in support of CBM initiatives. The model uses the first principles approach to analyze the rotating shafts and gear couplings using rotor dynamic analysis techniques. The helicopter transmission is presented, followed by a discussion of the finite element formulation to include gear mesh modeling methodologies. System natural frequencies and mode shapes are discussed, along with the model's validation procedure. The model's primary purpose is to simulate multiple operating conditions to include faults. One such fault condition simulates the wear of gear tooth contact surfaces. The nature of the fault and its modeling techniques are discussed. simulation results are presented in the time domain using a conventional vibration diagnostic parameter. A new diagnostic parameter, the FE2, is also introduced for detecting faults in the frequency domain. Additional considerations and further research points are also discussed. The results demonstrate the potential of physics-based, mathematical models in providing a key technology enabler for improving health monitoring and prediction capabilities of CBM strategies.
Large Eddy simulations (LES) were performed to predict the flame profile of bluff-body stabilized premixed flame at stable and blow-out conditions. Probability density function (PDF) based approach was used to solve t...
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ISBN:
(纸本)9781563479762
Large Eddy simulations (LES) were performed to predict the flame profile of bluff-body stabilized premixed flame at stable and blow-out conditions. Probability density function (PDF) based approach was used to solve the scalar transport by fully resolving the chemical source term with 14 species, 44 step propane reduced chemical kinetic mechanism using in situ Adaptive Tabulation (ISAT). The data from the Volvo experimental rig were used to validate the LES-PDF results for velocity, temperature and CO. simulations were also performed at AFRL validation rig conditions by varying the equivalence ratios to predict the flame dynamics at stable, unstable and blow-out conditions. Overall, the simulation results from the LES-PDF approach predicted the experimental data fairly well including the blow-out conditions. Results also show that the near-field wake behind the bluff body was dominated by Von-Karman vortex shedding for both the non-reacting case as well as the reacting simulation at blow-out conditions.
The use of modeling, simulation and analysis in defense systems acquisition is now being embraced by the Republic of Korea acquisition community for simulation-based design, simulation-based acquisition, and simulatio...
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The objective of this paper is to discuss and evaluate the two main approaches for night vision goggle (NVG) training currently applied in simulation and training. It describes the different techniques of NVG training...
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作者：
Landry Jr., Lloyd M.Modeling
Simulation and Labs Lockheed Martin Aeronautics Company Ft. Worth TX 76034 United States
This paper addresses the application of virtual modeling and simulation in the twenty Engineering Laboratories used by the F-35 Program for Design, Development, Integration, Test and Verification. These applications c...
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This presentation will cover Airplane Upset Recovery Training from one airplane manufacturer's perspective from 1995 to 2008. The reasons for developing the Upset Recovery Training Aid will be discussed, related a...
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