Tidal Response of Planetary Fluids (TROPF)
Creators: name: Tyler, Robert
Publisher: name: Zenodo
Year: 2019

description: This document provides a users's manual as well as application examples for the <em>Tidal Response Of Planetary Fluids</em>(<em>TROPF</em>) software package. In planetary science, the tidal response of fluid media (e.g. ocean, atmosphere, magma, core fluids) depends on input parameters that are not well constrained and must often be considered over a very wide range. This creates a computational challenge as millions of tidal scenarios may be required to adequately sample the solution domain describing the range of tidal response behavior. <em>TROPF</em>is designed and optimized to meet this challenge. The <em>TROPF</em>package includes several different solvers using either spherical-harmonic or finite-volume base functions. Using factorized sparse matrix operations, the primary solver (tropf.m) can provide high-resolution tidal response solutions at a rate of about 1 million solutions per minute on a standard desktop computer (each solution is, more specifically, for an individual vertical mode or layer.) Validations provided show that the different solvers provide solutions that agree with each other to within either machine precision or the theoretical limits of the resolution chosen. <em>TROPF</em>is developed in the <em>MATLAB</em>language but can also be run in <em>Octave</em>. Portability to <em>Python</em>and other languages is also fairly easy as the instructions for building the operator matrices are described here in detail and the coding of core <em>TROPF</em>routines adheres to generic sparse matrix operations and avoids functions specific to <em>MATLAB</em>. The equations solved by <em>TROPF</em>are generalized forms that cover the different governing equations used in a wide range of fluid tidal applications. In the simplest example of a thin, hydrostatic, uniform-density ocean, the equations solved reduce to the Laplace Tidal Equations and continuity equation. Extensions to this can include a wide variety of dissipation processes (e.g. Rayleigh drag, eddy viscosity including harmonic, biharmonic, and hyperharmonic forms) as well as other parameterized effects such as self gravity and coupling with an overlying ice shell. In applications to atmospheric tides (potentially thick, compressible, stratified, nonhydrostatic fluids) the equations solved are those from Classical Tidal Theory, which are understood here as representing a fairly general set of equations for conservation of momentum and energy but under the limitation that the horizontal and vertical dependencies remain separable (such that the separation of variables technique applies). Configuration scripts are included for running the demos and validation studies described in this manual. In addition, the Applications Chapter, includes a comprehensive suite of generic tidal studies covering the tides in two-body (synchronous as well as nonsychronous) systems. Specific applications can then be treated by using one of these examples as a starting template (or simply rescaling the results these examples already provide). It is expected that more examples will be added to these applications and it is therefore recommended that the user first ensure they have the latest software and documentation.