Source code for bladedesigner.camberlines.joukowskicamberline

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# ***************************************************************************
# *   Copyright (C) 2011-2013 by Andreas Kührmann [kuean@users.sf.net] and  *
# *   Fabian Schäffer                                                       *
# *                                                                         *
# *   This program is free software; you can redistribute it and/or modify  *
# *   it under the terms of the GNU General Public License as published by  *
# *   the Free Software Foundation; either version 3 of the License, or     *
# *   (at your option) any later version.                                   *
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# *   This program is distributed in the hope that it will be useful,       *
# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
# *   GNU General Public License for more details.                          *
# *                                                                         *
# *   You should have received a copy of the GNU General Public License     *
# *   along with this program; if not, write to the                         *
# *   Free Software Foundation, Inc.,                                       *
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# ***************************************************************************


import numpy as np

import bladedesigner.baseclasses as bcls
import bladedesigner.foundation as fdn


__all__ = ['JoukowskiCamberLine']


class JoukowskiCamberLine(bcls.AnalyticalCamberLine):
    """
    The Joukowski-Camberline is characterized by the maximum camber.
    Its geometry results from the Joukowski-Transformation, the camberline
    is defined for small bulges in the following form:
    """

    def __init__(self):
        super(JoukowskiCamberLine, self).__init__()
        # properties (initialized by user)
        self.__max_camber = fdn.Uninit('max_camber')
        # add user properties to initialization summary
        self._properties.append('max_camber')

    @property
    def max_camber(self):
        return self.__max_camber

    @max_camber.setter
    @fdn.restrict(new_max_camber=(int, float))
    def max_camber(self, new_max_camber):
        """
        Type: ``int or float``
        """
        if self.__max_camber != new_max_camber:
            self.__max_camber = new_max_camber
            self.update()

    @fdn.memoize
    def get_derivations(self):
        """
        get_derivations()

        Returns: ``ndarray``

        Calculates camber line derivations and returns them in an array.

        .. note:: **Note**

           The return value will be cached. Recalling this method returns the
           cached value, if the attribues are unchanged.
        """
        self._check_initialization()
        self._cached = True
        x = self.distribution(self.sample_rate)
        return self.max_camber * (1 - 2 * x)

    @fdn.memoize
    def as_array(self):
        """
        as_array()

        Returns: ``ndarray``

        Calculates camber line coordinates and returns them in an array.

        .. note:: **Note**

           The return value will be cached. Recalling this method returns the
           cached value, if the attribues are unchanged.
        """
        self._check_initialization()
        self._cached = True
        x = self.distribution(self.sample_rate)
        y = self.max_camber * x * (1 - x)
        return np.reshape(np.append(x, y), (-1, 2), "F")