Lecture 15, 18.300, Thu Mar 31, 2022. Summary New topic: Gas Dynamics, Acoustics, and Strings. % -------------------------------------------------------------------------- #050 Recall 1-D Euler eqns of Gas Dynamics. Explain BC for a pipe: close end and open end. #051 Polytropic gases and gamma-gas law. #050 Shallow water wave equations: rectangular channel & flat horizontal bottom. BC at closed end, or when discharging into a lake. Derive characteristic form: rho_t + u*rho_x + rho*u_x = 0 times +/- c/rho plus u_t + u*u_x + (c^2/rho)*rho_x = 0 ---> (u_t + C*u_x) +/- (rho_t + C*rho_x) = 0 \ Characteristic form. where C = u =/- c [characteristic speeds]. / % % ========================================================================== NOTE: Here #nnn are references to the Lecture Points file. [PSQ] means Problem Set Question. The "lecture summaries and points" are NOT intended as study materials. The points purpose is explained in the "lecture points" file. The summaries are brief descriptions each lecture, used by the instructor to keep track of the material covered. They ARE *NOT* "lecture notes" to be used to study and/or replace attending the lectures, etc. They are provided for your convenience, as a help to organize your own notes. % ========================================================================== % EOF