channel_LES

Large eddy simulation of turbulence in a straight channel

Author: Haining Wang

This is the C++ version of the Fortran program originally developed by Huang.

By using C++, the following advantages are achieved:

• Data and algorithms are decoupled by encapsulating modules into classes
• New fftw library supports arrays of arbitrary length

Meanwhile, several shortcomings of the original F77 implementation are avoided:

• The original implementation fails to fully utilize the unified syntax provided by the language
• The original implementation is procedural-oriented thus laking proper modularization
• The original implementation heavily depends on global variables and implicit data types throughout the code

The code includes the following modules:

• class Para: manages (IO, storing, etc) case parameters for the computations
• class Mesh: stores grid information, including the differential scheme coefficients and wave numbers for FFT
• class Field: stores flow fields of the primitive and intermediate variables & provides tools for basic operations (memory copy, IO, etc)
• class IDM: the actor class for the Implicit Decoupled Method, which is 2nd order in both time & space
• class Statis: holds tools for calculating basic statistics, useful for runtime monitoring and post-processing
• class Martix: holds functions for solving tri-diagonal matrix, which is the key to the high efficiency of the whole program

Reference:

Kyoungyoun Kim, et al. (2002). "An implicit velocity decoupling procedure for the incompressible Navier–Stokes equations." INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 38:125–138. [link]