Modeling and simulation

About: Modeling and simulation is a research topic. Over the lifetime, 10273 publications have been published within this topic receiving 111550 citations.

Modeling and simulation of turbulent polydisperse gas-liquid systems via the generalized population balance equation

Abstract: This article reviews the most critical issues in the simulation of turbulent polydisperse gas-liquid systems. The discussion is here limited to bubbly flows, where the gas appears in the form of separate individual bubbles. First the governing equations are presented with particular focus on the Generalized Population Balance Equation (GPBE). Then the mesoscale models defining the evolution of the gas-liquid system (e.g. interface forces, mass transfer, coalescence and breakup) are introduced and critically discussed. Particular attention is devoted to the choice of the drag model to properly simulate dense gas-liquid systems in the presence of microscale turbulence. Finally the different solution methods, namely Lagrangian and Eulerian, are presented and discussed. The link between mixture, two- and multi-fluid models and the GPBE is also analyzed. Eventually the different methodologies to account for polydispersity, with focus on Lagrangian or Direct Simulation Monte Carlo (DSMC) methods and Eulerian Quadrature-based Moment Methods (QBMM), are also presented. A number of practical examples are discussed and the review is concluded by presenting advantages and disadvantages of the different methods and the corresponding computational costs

A method for landing gear modeling and simulation with experimental validation

Abstract: This document presents an approach for modeling and simulating landing gear systems Specifically, a nonlinear model of an A-6 Intruder Main Gear is developed, simulated, and validated against static and dynamic test data This model includes nonlinear effects such as a polytropic gas model, velocity squared damping, a geometry governed model for the discharge coefficients, stick-slip friction effects and a nonlinear tire spring and damping model An Adams-Moulton predictor corrector was used to integrate the equations of motion until a discontinuity caused by a stick-slip friction model was reached, at which point, a Runga-Kutta routine integrated past the discontinuity and returned the problem solution back to the predictor corrector Run times of this software are around 2 mins per 1 sec of simulation under dynamic circumstances To validate the model, engineers at the Aircraft Landing Dynamics facilities at NASA Langley Research Center installed one A-6 main gear on a drop carriage and used a hydraulic shaker table to provide simulated runway inputs to the gear Model parameters were tuned to produce excellent agreement for many cases

Matrix converter induction motor drive: modeling, simulation and control

Abstract: This paper presents a model in Simulink, which consists of a three-phase matrix converter, an induction motor, a field-oriented controller, and a power supply. A simplified Venturini's modulation algorithm is used in the simulation model. This algorithm provides unity fundamental displacement factor at the input regardless of the load displacement factor and can be easily implemented in closed loop operation. Simulation results are presented for both input and output sides of the converter. These results demonstrate a high-performance matrix converter-fed induction motor drive with unity input displacement factor.

Active control of beam structures with piezoelectric actuators and sensors: modeling and simulation

Abstract: The active damping of structures is an important emerging field. In this context, it is necessary to be able to develop new control methods for flexible structures and simulate their effects. In order to be able to deal with the optimization of active device locations, spillover and any other general problems linked to control and model reduction, a simple but sufficiently rich model is very useful. This is the reason why this technical note deals with the modeling and simulation of the active vibration control of beam structures using piezoelectric actuators and sensors. In order to model beam structures equipped with piezoelectric devices, we develop a simple finite composite beam element, taking into account the properties of piezoelectric elements. This model uses six mechanical degrees of freedom and four electric degrees of freedom. Then, a linear quadratic regulator method is used to compute the control, including the implementation of a state observer. Several simulations are presented.