What is Fdm: Definition and 23 Discussions

fdm (fetch/filter and deliver mail) is a mail delivery agent and email filtering software for Unix-like operating systems, similar to fetchmail and procmail. It has been started in 2006 by Nicholas Marriott who later also started tmux in 2007.

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  1. Z

    I Can FDM solve any type of PDE same as FEM?

    hello aside from some constraints such as an irregular integration domain, can FDM solve any type of PDE same as FEM ?
  2. Hosein Javanmardi

    A Implementing FDM Boundary Conditions at a Red Point

    in Finite Difference Method (FDM), the boundary conditions can be implemented by applying the continuity of parallel component of magnetic field intensity. when it comes to the interface of two areas, it is done at ease, but consider this case at the red point: in FDM we exactly require on...
  3. J

    Health risks of ABS FDM (3d printing)

    This is not the first study I've seen discussing potential risks of FDM airborne byproducts. It's the reason I bought a fully enclosed unit. However, it's in my home which at the moment is extremely small. It's less than a meter away from both my workbench and my sleeping area. While the unit is...
  4. maistral

    A FDM vs FEM: Which is Better for CFD?

    Basically, the summary. I forgot where I read this before, apparently FDM is much better in handling such problems, and apparently CFD in general is better dealt with FDM instead of FEM. Why is this so?
  5. Riverbirdy

    Finite difference Method of Wave Equation

    Hi, Physics forum! Just a little push of my doubts I hope somebody could help me with my confusion of one of our home works. I know that all boundary conditions are zero. My doubt is how do I interpret (x,y,0)=0.01 source in the figure? Where is it located in the grid. I am hoping someone...
  6. W

    FDM simulation of an electrical transformer?

    My goal is to program a FDM simulation of a transformer. So, we have the coupled inductor model to start with ... However, if L1 = 1, L2 = 9, and coupling is perfect then M = sqrt(1*9) = 3 and L1 - M = -2. So, this seems problematical to me. Also, if I try to simulate this model using SPICE...
  7. Federico Navarrete

    FDM for a 3 metal layers 3D, heat transfer

    Dear members, Some days ago, I received the following exercise but I have never studied thermodynamics before and I don't know very well where to start, the exercise is about Heat Transfer and the Finite Difference Method and I must program the solution using Petsc and C++. About the Finite...
  8. N

    Stability condition for solving convection equation by FDM

    Hi, I know, there is a stability condition for solving the Convection-Diffusion equation by Finite Difference explicit/implicit technique, which is \Delta t<=(\Delta x)^2/(2*D) for one-dimensional or \Delta t<=((\Delta x)^2+(\Delta y)^2)/(8*D) for two-dimensional problem, where D is the...
  9. N

    MATLAB 3D Finite different method using matlab

    Can anyone show me how to solve the 3D diffusion equation which has been modeled into FDM by using matlab?
  10. K

    Poisson PDE in polar coordinates with FDM

    I want to solve a Laplace PDE in a polar coordinate system with finite difference method. and the boundary conditions: Here that I found in the internet: and the analytical result is: The question is how its works? Can I give an example or itd?Thanks
  11. R

    2D cylindrical heat equation

    Hello friends, I am new for numerical methods and programming. i have been trying to devolop a program in 2D poisson heat equation in cylinder (r,angle) by finite difference method ∂2u/∂r2 + 1/r * ∂u/∂r + 1/r2 * ∂2u/∂θ2 = Q(u,θ)discritized equation :- ui+1,j − 2uij + ui−1,j/(∆r)2 + 1/ri *...
  12. R

    How to Optimize a 2D Nonlinear Heat Conduction Solver in MATLAB?

    Hi friends, i have developed an code for a non linear heat conduction in 2 dimensions with dirichlet boundary condition by finite difference method in Matlab. my code is running slow to give output. If anybody has any idea of solving this equation or have written any Code for this equation...
  13. R

    Stress analysis of a cantilever beam using FDM

    I am a CSE researcher with a not so in depth background of physics. As a part of my research in object modelling, I am trying to computationally figure out the stress for various objects by using Finite Difference Method (not FEM which is the defacto standard for stress analysis). The reason for...
  14. A

    FDM Heat Equation FTCS Scheme with NBC

    Homework Statement I have a quiz question that I'm struggling with. We've been working on using a FTCS scheme with two Essential Boundary Conditions, and now I have a problem with one EBC (ie static) and a Natural Boundary Condition (ie a derivative). The condensed problem statement: u_{t} =...
  15. S

    Solving Poisson Equation by using FDM

    I need help from anyone urgently, I need C code for Solving Poisson Equation has known source with Neumann condition by using FDM (finite difference method) in 2D problem.
  16. H

    Numerical analysis (FDM) with MATLAB

    Homework Statement HOW Can i make graph from MATLAB? Applying FDM in numerical analysis I 'M Beginner in MATLAB PLZ HELP ME! you are definitely Kind Global students! The Attempt at a Solution Homework Statement Homework Equations The Attempt at a Solution Homework Statement Homework...
  17. Q

    FDM vs OFDM: Exploring Overlap & ICI

    I was working on my thesis when this question popped into my head, why can't there be overlap in FDM wihout ICI but you are allowed to overlap in OFDM without ICI? Also why is the maximum overlap of subchannels 50% in OFDM before ICI occurs? From math point of view as long as the carriers are...
  18. S

    Solving the 2D Heat Equation with FDM and Gauss-Seidel Method

    Homework Statement Given a steady-state heat transfer for a 100mx100m plate, to be discretized to 6 nodes, governed by a heat tranfer equation: U_xx + U_yy = 0 Given dirichlet boundary conditions: U(0,y)=50, U(100,y) = 100,, neumann boundary: U_y(x,0)=0, U_y(x,100) = 0. Find the...
  19. I

    Numerical FDM - wave equation - boundary conditions question

    Hello everyone and greetings from my internship! It's weekend and I'm struggling with my numerical solution of a 1+1 wave equation. Now, since I'm eventually going to simulate a black hole ( :D ) I need a one-side open grid - using advection equation as my boundary condition on the end of my...
  20. T

    Investigating Unexpected Power Increase with Analogue FDM

    Hi guys, I am trying to implement Analogue FDM on top of my single carrier modulation (eg: QAM and QPSK) of Multi carrier modulation (eg: OFDM). For an example, I have two different pair of I and Q channels, where first pair is upconverted at 2.2 GHz and the next pair at say 2.7 GHz and them MUX...
  21. T

    Can FDM be Used to Multiplex OFDM Signals at Different Frequencies?

    Hi guys, I'm currently generating OFDM signal and send it to DAC and then upconvert them to 1 GHz carrier signal. I want to multiplex several of them, like say I upconvert them to 1 GHz, 800 MHz, 1.2 GHz, which represents 3 different signals, then multiplex them together using FDM, is it...
  22. D

    ODE with Neumann (FDM)

    Homework Statement Use finite difference central method to approximate the second-order Ordinary Differential Equation U''(x) = e^x over domain [0, 1] where: u(1) = 0 (Dirichlet Bound) U'(0) = 0 (Neumann Bound) Homework Equations let 'h' be the change in x direction The Attempt...
  23. A

    Coupled conductive-convective heat transfer using FDM

    Now I need to solve a transient problem involving both conduction and convection. Homework Statement In this problem there's a thin plate being heated by two constant-temperature sources. One small source is in contact with part of the plate. Another one is separated with the plate by air...