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In the quest for more realistic string sound synthesis, nonlinear (large-amplitude) effects have recently come under scrutiny. Though a mathematical description of the coupled longitudinal/transverse motion of such a string is straightforward, the development of numerical methods (and thus synthesis algorithms) is complicated due to stability considerations; frequency domain analysis cannot be fruitfully...
In this paper, the synthesis of a network of local controllers for the purpose of controlling the transition from laminar to turbulent flow is presented, using a recently proposed spatially interconnected model of plane Poiseuille flow. Measured feedback signals used by the controllers are the local changes in wall shear force, and the generated control action is a local change in fluid wall normal...
Physical systems are mostly modelled by differential equations together with initial conditions and boundary conditions. For systems showing some kind of ‘memory’ local differential equations are not appropiate. Particularly in the description of damping behaviour of vis-coelastic media, fractional differential equations are suggested instead by many authors. Many of these approaches use ad hoc definitions...
Various optimization problems associated with the optimal control of distributed parameter systems with retarded arguments appearing in the boundary conditions have been studied recently by [1]-[8] and [11], [12]. In this paper, we consider an optimal distributed control problem for a linear hyperbolic system in which multiple time delays appear in the integral form in the Neumann boundary condition...
A novel linearized model for the transition control problem in plane Poiseuille flow has been proposed recently. The model is based on a finite difference approach in streamwise direction and a spectral approach in wall normal direction. It is thus valid for all spatial frequencies and can be used for the synthesis of controllers for flow control problems, using recently developed ideas for spatially...
Spatial discretisation of fluid mechanical systems typically leads to descriptor systems consisting of large numbers of differential algebraic equations (DAEs). In an effort to apply standard control theory to such systems, physical insight is often used to analytically reformulate the DAE as an ordinary differential equation (ODE). In general, this is a difficult process that typically requires expert...
This paper describes the relationship between the boundary thermal resistance and the hot spot temperature in power Si MOSFET. Power Si MOSFET is widely used semiconductor device in various area, for example car electronics. Since high voltage is applied to power Si MOSFET, high electric field (more than 10 V/m) is generated. Under such high electric field, electron thermal energy becomes much higher...
Symmetry breaking refers to the existence of solutions that break the original symmetries of the underlying nonlinear system. In nonlinear optics with Kerr nonlinearity, symmetry breaking has been studied in serval complex structures by some approximate semi-analytical methods. In this paper, we develop an efficient numerical method to rigorously analyze symmetry breaking in a simple system of two...
A new boundary integral method for solving the general Helmholtz equation has been developed starting from the frequency independent Laplace's equation. The new formulation is based on the Method of Moments solution of Laplace's equation. The main feature of this new formulation is that the boundary conditions are satisfied independent of the region node discretizations. The numerical solution of...
The purpose of this paper is to present the investigation of impact pressure acting on the hemisphere cylinder when it hits the water. In this paper, a two-dimensional hemisphere cylinder is built to simulate the water-entry problem. The model enters into the calm water verticals with initial velocity in y-direction at 10m/s. The transient flow simulation is carried out using Fluent k-£ turbulent...
In this paper, we consider the quasilinear parabolic-elliptic repulsion chemotaxis system with logistic source under homogeneous Neumann boundary condition in a smooth bounded domain. It is proved that the classical solutions to the corresponding initial boundary value problem are uniformly bounded in time.
This paper introduces a novel approach for image edit. Instead of solving poisson equation, image edit task can be treated as in painting the region of interest by propagating the boundary differences between target and source image. Based on the Fast Marching Method, differences along the boundary can be progressively eliminated to interior layer by layer, and we can get a seamless edit result. It...
The change of ship's characteristic length can change scientific researching method. The paper gains the calculation parameters of Green function and the relational expression of vessels' characteristic length by establishing the analysis theory of ships' characteristic length dimension based on the control equation of green function and gives the statistical expression for ships' characteristic length...
This paper investigates the analytical solution of the steady step period in one-period limit cycle walking. First, we introduce the active combined rimless wheel (CRW) model with motor to analyze the steady walking state when the CRW is walking on the level ground. Second, the initial and terminal boundary conditions of n-period control systems are analyzed to calculate steady walking periods by...
The objective of this work is modeling the interaction between pulsatile blood flow and arterial walls. We model blood flow in arteries as an incompressible viscous fluid with Newtonian rheology, confined by a poroelastic arterial wall modeled with the Biot equations. We propose loosely coupled solution strategy of the fluid-structure interaction problem, which allows solving the Navier-Stokes and...
In this paper, we firstly give the fundamental solution for Beltrami equation. Secondly, based on symmetric extension, we investigate the solution of a Hilbert Boundary Value Problem (BVP, for short) for Beltrami equation by converting it to corresponding Riemann BVP and obtain the explicit representation of solutions.
Based on the generalized piezoelectric-thermoelastic theory, the performance of imperfect interface on the dynamic response of an infinite extent piezoelectric plate excited by thermal shock is presented. As a simple case, we first investigate the behaviors of a single-layered plate which is traction free and applied thermal shock. After that a double-layered plate with imperfect interface is studied,...
Based on the simplified theory, free vibration in three-dimensional functionally graded piezoelectric plates is analyzed. The first-order shear deformation theory and state space method are utilized in directions z and x, respectively. The plate is simply-supported in direction y, so a generalized Levy solution is obtained. Numerical examples show that the vibration behavior depends considerably on...
The dispersion functions of Rayleigh waves are theoretically deduced in layered half-space, which consist of elastic and porous layers. Different with the Rayleigh waves of elastic half-space, the dispersion function changes when the porous layer exists, and relates with the position of porous layers. The dispersion functions are given in cases of the porous layers locating at different positions...
In this paper a state observer for a distributed parameter system (DPS) with nonconstant parameter functions is presented. The DPS describes the freezing of foodstuff in vertical plate freezers and is a nonlinear heat equation. The observer is based upon the Extended Kalman Filter, meaning that the nonlinear heat equation has been discretized in the spatial domain before designing the observer. We...
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