From the Publisher: Presents developments in computational techniques pertaining to moving boundary problems in fluid dynamics. It describes several computational techniques which can be applied to a variety of proble...
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ISBN:
(纸本)1560324589
From the Publisher: Presents developments in computational techniques pertaining to moving boundary problems in fluid dynamics. It describes several computational techniques which can be applied to a variety of problems in thermo-fluid physics, multi-phase flow, and applied mechanics which involve moving flow boundaries. The book demonstrates the application of a variety of techniques for the numerical solution of moving boundary problems within the framework of the finite-volume approach, with appropriate examples.
作者：
Cash, GGEnvironmental Effects Branch
Health & Environmental Review Division Office of Pollution Prevention & Toxics U.S. Environmental Protection Agency SW USA
A fast computer algorithm is described which brings computation of the permanents of sparse matrices, specifically, chemical adjacency matrices, within the reach of a desktop computer. Examples and results are present...
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A fast computer algorithm is described which brings computation of the permanents of sparse matrices, specifically, chemical adjacency matrices, within the reach of a desktop computer. Examples and results are presented, along with a discussion of the relationship of the permanent to the Kekule structure count. Also presented is a C-language implementation which was deliberately written for ease of translation into other high-level languages.
We designed, implemented, and tested a real-time flexible controller for manipulating different types of robots and control algorithms. The robot-independent, IBM PC-based multiprocessor system contains a DSP56001 mas...
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We designed, implemented, and tested a real-time flexible controller for manipulating different types of robots and control algorithms. The robot-independent, IBM PC-based multiprocessor system contains a DSP56001 master controller, six independent HCTL-1100 joint processors for accurate robotic joint control, and an interface computer board for processor communication, The joint processors operate in four user-defined modes and can be connected directly to an incremental optical encoder, which accommodates specialized applications and eliminates extra hardware.
We propose delegated tuning and forwarding (DTF), a new architecture for dynamically assigning wavelength channels in a ''broadcast star'' optical network. DTF exploits tunable components without makin...
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We propose delegated tuning and forwarding (DTF), a new architecture for dynamically assigning wavelength channels in a ''broadcast star'' optical network. DTF exploits tunable components without making excessive demands on tuner agility by combining the tuning on demand of receivers with the forwarding of packets over a logical topology. We describe the control algorithms of DTF and prove some results establishing their stability and robustness. We show by simulation that DTF achieves lower hop-counts in conditions of light-to-moderate load than do DeBruijn graph networks. When a DTF network is saturated, the average number of hops in each path is only about 10% higher than the average for a DeBruijn graph network, suggesting that, even under high loads, the evolution of network topology under DTF is close to optimal.
In this paper, the problem of active sound cancellation in finite-length ducts is investigated. The closed-form solution of a one-dimensional wave equation is obtained as the plant model. The controllability, observab...
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In this paper, the problem of active sound cancellation in finite-length ducts is investigated. The closed-form solution of a one-dimensional wave equation is obtained as the plant model. The controllability, observability, and transmission zeros are discussed based on the transfer function model. For ducts with totally reflective boundaries, stabilization can be achieved by using a speaker (actuator) and a microphone (sensor). Cases of collocated and noncollocated sensors and actuators are presented. A repetitive control algorithm was developed to drive the actuator so that harmonic noises in a duct are attenuated. For a duct with partially reflective boundaries, the application of repetitive control prevents sound from leaking out of the duct at a chosen end. A simulation study demonstrating the effects of this feedback control scheme is also presented.
The robustness of the popular PI and PID controllers is studied in this paper. The controller is first optimally tuned for nominal process conditions. Then, errors representing uncertainty in the process parameters ar...
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The robustness of the popular PI and PID controllers is studied in this paper. The controller is first optimally tuned for nominal process conditions. Then, errors representing uncertainty in the process parameters are introduced in the process model and their effects on the closed-loop performance are evaluated. The results quantitatively confirm that these simple control algorithms are robust.
This paper presents a new feedback congestion control mechanism for the how control of the best effort (ABR) traffic in ATM networks, This new mechanism belongs to the class of feedback control schemes that ensure no ...
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This paper presents a new feedback congestion control mechanism for the how control of the best effort (ABR) traffic in ATM networks, This new mechanism belongs to the class of feedback control schemes that ensure no data losses and operate based on simple 'stop' and 'start' signals, A novelty presented by this paper is a methodology which, for a given set of desired properties, leads to the specification of the corresponding control algorithm. For the case of a single connection, the algorithm can operate with the theoretically minimum possible buffer size, Interestingly, the algorithm obtained has a different structure than the previous schemes;it does not operate based on fixed high and low thresholds, A new congestion control mechanism is subsequently derived for the flow control of multiple connections, The new scheme is exercised hop-by-hop and on a per-connection basis, This scheme allows connections to share memory and bandwidth resources efficiently within the network, The performance of the new scheme is also presented, and its statistical multiplexing efficiency is demonstrated. The measures investigated include buffer occupancy, average delay, overhead due to the protocol signals, and sustained throughput, In the case of long propagation delays, the buffer savings achieved by the new scheme are substantial.
A new approach to control the speed and rotor flux of an induction motor using the theory of the sliding-mode is presented. Sabanovic's equations for an induction motor are first modified to a state space form sui...
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A new approach to control the speed and rotor flux of an induction motor using the theory of the sliding-mode is presented. Sabanovic's equations for an induction motor are first modified to a state space form suitable for the present design of the algorithm. For controlling the speed and rotor flux of the drive, a simple control algorithm is proposed based on the existence of a certain positive definite matrix. Lyapunov direct method is used to ensure the reaching and sustaining of sliding-mode. Obviation of flux measurement is achieved through manipulation of Stanley's equations. Simulation studies are conducted. The control algorithm exhibits excellent drive performance in the presence of load disturbances and stator and rotor resistances changes up to 100% of the nominal values.
The on-going development of a full authority digital engine control (FADEC) system for the US Navy's Intercooled Recuperated (ICR) gas turbine requires a high level of system coordination to achieve the primary be...
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The on-going development of a full authority digital engine control (FADEC) system for the US Navy's Intercooled Recuperated (ICR) gas turbine requires a high level of system coordination to achieve the primary benefits of reduced specific fuel consumption and improved specific output power relative to a simple cycle engine. This paper describes the system requirements analysis and the implementation of control algorithms leading to the preliminary ICR control system design. The ICR control system is required to coordinate the actions of over 30 actuators using data taken from over 150 sensors. Primary control of the engine output power is provided by regulation of the fuel metering valve. Thermal management of the intercooler, recuperator, and variable area power turbine nozzle results in maximum cycle efficiency within safe operating limits. The new electronic engine controller (EEC) is based on a new open architecture Futurebus + backplane and is fully redundant in all operationally critical control functions. The EEC also features an operating panel and video display for local operation and maintenance of the control system. The graphic display and function keys provide access to control functions as well as assisting maintenance activities with built-in test diagnostics to trouble shoot failed circuitry.
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