Program 7A & 7B Unitless 1D FDTD Open Boundary with Courant Factor less than 1

Evolution of high frequency ripples along with signal decay in 1D FDTD with Courant factor < 1

Youtube Links :- http://www.youtube.com/watch?v=i6br1Yfu-x4
http://www.youtube.com/watch?v=tpsm40wvBtg

Written for Course :-
Computational Electromagnetics, Fall 2011
Department of Electrical Engineering
Indian Institute of Technology Madras (IITM)
Chennai - 600036, India

Authors :-
Sathya Swaroop Ganta, B.Tech., M.Tech. Electrical Engg.
Kayatri, M.S. Engineering Design
Pankaj, M.S. Electrical Engg.
Sumantra Chaudhuri, M.S. Electrical Engg.
Projesh Basu, M.S. Electrical Engg.
Nikhil Kumar CS, M.S. Electrical Engg.

Instructor :-
Dr. Ananth Krishnan
Assistant Professor
Department of Electrical Engineering
Indian Institute of Technology Madras
http://www.ee.iitm.ac.in/~ananthk

Description :-

In this program, the Courant-Friedrich-Levy factor (or Courant Factor) is deliberately pushed to less than 1 for a decaying solution. It should be noted that for 1D FDTD, the magic FDTD timestep corresponds to Courant Factor of 1. Courant Factors less than 1 , are inherently stable (they are not unstable), but apart from Gaussian sources, other types of sources have significant high frequency noise in the form of ripples. If you find ripples in your program for Impulse or Continuous hard source, you should now know that you have a Sub-Optimal Courant factor.