pencil.calc.draglift
====================

.. py:module:: pencil.calc.draglift

.. autoapi-nested-parse::

   Contains classes and methods to compute drag, lift and Strouhal number
   for a cylinder in a cross flow



Classes
-------

.. autoapisummary::

   pencil.calc.draglift.Draglift


Functions
---------

.. autoapisummary::

   pencil.calc.draglift.draglift
   pencil.calc.draglift.find_extrema


Module Contents
---------------

.. py:function:: draglift(simulations, sortby='dx', **kwargs)

   Compute mean drag coefficient, rms lift coefficient, and Strouhal number
   for flow past a circular cylinder.
   If the flow is steady, only drag and lift coefficients are computed.

   Call signature:
     draglift(simulations, d_cylinder=0.1, u_0=1.0, flow_dir='y',
              t_start=-1, sortby='dx'):

   Keyword arguments:

   *simulations*
     array of simulation names to be included in the computations

   *d_cylinder*:
     diameter of the cylinder

   *u_0*
     velocity at the inlet

   *flow_dir*:
     direction of the flow

   *t_start*
     time to start the drag computations from
     should be where the a steady vortex shedding has developed

   *sortby*
     property to sort the arrays by
     typical choices for parametric studies are grid size, length of domain, etc.

   Returns
     object with information: sim-name, drag (mean), lift (rms), and st (non-dim shedding frequency)


.. py:class:: Draglift

   Bases: :py:obj:`object`


   Grid -- holds pencil code time grid data.

   Fill members with default values.


   .. py:attribute:: name
      :value: ''



   .. py:attribute:: drag
      :value: 0



   .. py:attribute:: lift
      :value: 0



   .. py:attribute:: st
      :value: 0



   .. py:method:: set_name(simulation)


   .. py:method:: compute(simulation, d_cylinder=0.1, u_0=1.0, flow_dir='y', t_start=-1)

      Compute the drag coefficienc, rms drag, lift coefficient, rms lift and Strouhal number of a given time series
      Requires time series T as input, on the form given in the pencil code where T.t, T.c_dragx and T.c_dragy are avaliable quantities
      Cylinder diameter, fluid mean velocity , flow direction and start time of drag computations velocity should also be given as input.



.. py:function:: find_extrema(series, maxmin)

   Input: Data series, extrama of intereset (max or min)
   Use scipy to find this
   scipy.signal.argrelextrema(array type of np,comparison operator eg np.greater or np.less)