Source code for bladedesigner.camberlines.acamberline

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

# ***************************************************************************
# *   Copyright (C) 2011-2012 by Andreas Kührmann [kuean@users.sf.net]      *
# *                                                                         *
# *                                                                         *
# *   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__ = ['ACamberLine']


class ACamberLine(bcls.AnalyticalCamberLine):
    """
    some documentation
    """

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

    @property
    def angle_of_inflow(self):
        r"""
        Type: ``int or float`` - values between (exclusive) 0 and :math:`\pi`
        only
        """
        return self.__angle_of_inflow

    @angle_of_inflow.setter
    @fdn.restrict(new_angle_of_inflow=fdn.OpenInterval(0, np.pi))
    def angle_of_inflow(self, new_angle_of_inflow):
        if self.__angle_of_inflow != new_angle_of_inflow:
            self.__angle_of_inflow = new_angle_of_inflow
            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
        chi = self.angle_of_inflow
        sign = 1 if chi < np.pi / 2 else -1
        r2 = (.5 / np.cos(chi)) ** 2
        x = self.distribution(self.sample_rate) - .5
        return  sign * x / np.sqrt(r2 - x ** 2)

    @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
        chi = self.angle_of_inflow
        sign = -1 if chi < np.pi / 2 else 1
        r2 = (.5 / np.cos(chi)) ** 2
        x = self.distribution(self.sample_rate)
        y = sign * (np.sqrt(r2 - (x - .5) ** 2) - np.sqrt(r2 - .25))
        return np.reshape(np.append(x, y), (-1, 2), "F")