# SIMPLEDDY is the jOceans module of jLab.

``` SIMPLEDDY  Streamfunction, velocity, and vorticity for various eddy profiles.

[V,PSI,ZETA]=SIMPLEDDY(R,RO,VO) returns the streamfunction PSI,
azimuthal velocity V, and relative vorticity ZETA at radial locations R
for the Rankine vortex.

The eddy core radius is RO, in km, and at this radius the eddy
currents achieve their maximum value of |VO| cm/s.  The sign of VO
gives the rotation sense of the eddy, positive for counterclockwise.

PSI has units of km^2/s, V has units of cm/s, and ZETA of 1/s.

RO and VO should either be scalars or an arrays of the same size as R.
The output arrays will have size LENGTH(R) x N.
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Eddy models

SIMPLEDDY can also return profiles associated with various other types
of model eddies.  The following forms are available:

SIMPLEDDY(R,RO,VO,'rankine')        -- Rankine vortex   [default]
SIMPLEDDY(R,RO,VO,'gaussian')       -- Gaussian vortex

RO, VO, and the shape parameter ALPHA may then each be either scalars
or arrays of the same length.
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Eddy 'slices'

SIMPLEDDY can also be used to return an eddy 'slice', that is, the
eddy streamfunction, currents, and vorticity observed along a curve.

CV=SIMPLEDDY(CX,RO,VO,...) where CX=X+iY is an array of locations on
the complex plane, with units of kilometers, returns the complex-valued
currents CV=U+iV due to an eddy located at the origin.

[CV,PSI,ZETA]=SIMPLEDDY(CX,RO,VO,...) also returns the streamfunction
and vorticity observed along this curve.
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'simpleddy --f' makes some sample figures.

Usage: [v,psi,zeta]=simpleddy(r,RO,VO);
[v,psi,zeta]=simpleddy(r,RO,VO,'gaussian');
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This is part of JLAB --- type 'help jlab' for more information
(C) 2015--2020 J.M. Lilly --- type 'help jlab_license' for details
```