Shallow Water or Diffusion Wave Equations - United States Army
HEC-RAS has three equation sets that can be used to solve for the flow moving over the computational mesh, the Diffusion Wave equations; the original Shallow Water equations (SWE-ELM,...
Diffusion Wave - an overview | ScienceDirect Topics
Direct substitution of the DSWa of the momentum equation in the mass conservation equation yields the classical (DWE) Diffusion-Wave Equation: (22) ∂ h ∂ t = ∇ · β ∇ z s + q where β = R h 2 / 3 h n ∇ z s 1 / 2 ; h is the water depth [L] and q is source/sink flux term [LT − 1 ].
Diffusion Wave Approximation to the Shallow Water Equations
Under the conditions described in this section, the Diffusion Wave equation can be used in place of the momentum equation. It will be seen in subsequent sections that the corresponding model...
Diffusion-Wave Equation Solver - United States Army
Diffusion-Wave Equation. The DWE describes the conservation of mass and momentum. A discrete DWE is obtained by substituting the diffusion-wave approximation for the velocity into the above...
1 The Diffusion Equation This course considers slightly compressible fluid flow in porous media. The differential equation governing the flow can be derived by performing a mass balance on the fluid within a control volume. 1.1 One-dimensional Case First consider a one-dimensional case as shown in Figure 1: A ∆x z y x
By applying a Fourier transform, we easily obtain a sort of pseudo-wave Helmholtz equation: where k(r,w) is the complex diffusion wavenumber. The term F(r), which is usually a constant, is the square of the characteristic decay length of the diffusion wave.
Linear Fractional Diffusion-Wave Equation for Scientists and …
This book systematically presents solutions to the linear time-fractional diffusion-wave equation. It introduces the integral transform technique and discusses the properties of the Mittag-Leffler, Wright, and Mainardi functions that appear in the solutions.
The fundamental solutions for the fractional diffusion-wave equation ...
Nov 1, 1996 · The time fractional diffusion-wave equation is obtained from the classical diffusion or wave equation by replacing the first- or second-order time derivative by a fractional derivative of order 2β with 0 < β ≤ 1 2 or 1 2 < β ≤ 1, respectively.
A compact difference scheme for the fractional diffusion-wave equation ...
Oct 1, 2010 · In this article, we constructed a compact difference scheme for the fractional diffusion-wave equation and proved the solvability, unconditional stability and L ∞ convergence by energy method. The numerical results show that the scheme is …
Laplace, Diffusion, and Wave Equations - math.wpi.edu
Nov 1, 2006 · Laplace, Diffusion, and Wave Equations Introduction The purpose of this lab is to aquaint you with partial differential equations. Background Second-order partial derivatives show up in many physical models such as heat, wave, or electrical potential equations. For example, the one-dimensional wave equation
- Some results have been removed