compute_enst: Compute the Norm of the Curl from the given mesh

In Will-McD/ENSTvisualise: What the Package Does (One Line, Title Case)

Compute the Norm of the Curl from the given mesh

Description

Calculates the normal curl from the given 3x3x3 grid about the center of the grid,the curl is calculated through numerical approximations of partial derivatives across the grid boxes adjacent to the central box.

Using the cross configuration, the central cross (the boxes in face to face contact with the central box ignoring the corner boxes of the 3D array), can be used to calculate the curl around the central box within the 3x3x3 array of velocities. Therefore 9 partial derivatives will be numerically approximated from the 3x3x3 array, as shown in the equation below:

Curl of f(x,y,z) = ( (dz/dy - dy/dz)i , (dx/dz - dz/dx)j , (dy/dx - dx/dy)k )

The curl is calculated using simulaiton length units Mpc /h and velocity units Mpc/h /Gyrs from SURFS, therefore, enstrophy is given in Gyrs^-2.

If normalised the value returned is unitless, given the normalization value is in Gyrs^2

Usage

compute_enst(X, Y, Z, ds, noise = T, normalise = NULL)

Arguments

X, Y, Z	A 3 x 3 x 3 array with each cell containing the mean velocity of the particles within each cell over-layed on the halo w.r.t with the x,y and z axis
ds	The side length of the cells within the grid
noise	A boolean value determining if numerical noise should be calculated in determining the curl of the velocity field. It is naturally set to True
normalise	An optional value, normalizes the enstrophy and error returned. The normalize value in units of Gyrs^2

Will-McD/ENSTvisualise documentation built on June 24, 2022, 5:13 p.m.