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Thomas Lambert authored- Use the proper syntax to take advantage of Matlab formatting and links in help. - Add more details and reformulate some stuff.
Thomas Lambert authored- Use the proper syntax to take advantage of Matlab formatting and links in help. - Add more details and reformulate some stuff.
Polar.m 7.83 KiB
classdef Polar
% POLAR Airfoil polars and some associated properties.
% The Polar class is used to store an airfoil polars (cl, cd, cm values for different angles
% of attacks, at different Reynolds and Mach numbers).
% It can also contain some interesting extra properties such as the stall point, the zero-lift
% points, the linear lift range. It is also possible to compute the extrapolation of the
% polars over the complete range of angles of attack if needed.
%
% Note:
% - One Polar object correspond to one Airfoil. The properties of the Polar object are
% vectors/matrices whose the columns represent a single polar curve.
% - The method 'loadpolar' can be used instead of the constructor to load a previously saved
% polar object.
% -----
%
% Polar properties:
% reynolds - Rynolds number of each polar curve, [-]
% mach - Mach number of each polar curve, [-]
% nCrit - nCrit number of each polar curve, [-]
% aoa - Angles of attack (one column per Reynolds), [rad]
% cl - Lift coefficient (one row per aoa, one column per Reynolds), [-]
% cd - Drag coefficient (one row per aoa, one column per Reynolds), [-]
% cm - Moment coefficient (one row per aoa, one column per Reynolds), [-]
% Ext - Struct with the data of the extended polars
% Stall - Struct with the data of the stall point for each curve
% Zero - Struct with the data of the zero-lift point for each curve
% Lin - Struct with the data of the linear range each curve
%
% Polar methods:
% Polar - Constructor
% loadpolar - Load a polar from the MAT-file
% extendpolar - Extend polar curves over [-pi, pi]
% findstall - Find stall point
% findzerolift - Find zero-lift point
% findcllinrange - Find lift curve linear range
% analyze - Runs the above three functions
% plotpolars - Plot the polars
%
% Polar constructor:
% Pol = Polar() creates an empty object.
%
% Pol = Polar(reynolds, aoa, c_l) creates a polar object with only the lift coefficient data.
%
% Pol = Polar(reynolds, aoa, c_l, c_d, c_m) creates a polar object with only the lift and drag
% coefficients data.
%
% Pol = Polar(reynolds, aoa, c_l, c_d, c_m) creates a polar object with the data for the lift,
% drag and moment coefficient.
%
% Constructor input:
% reynolds : Rynolds number of each polar curve, [-]
% aoa : Angles of attack (one column per Reynolds), [rad]
% cl : Lift coefficient (one row per aoa, one column per Reynolds), [-]
% cd : Drag coefficient (one row per aoa, one column per Reynolds), [-]
% cm : Drag coefficient (one row per aoa, one column per Reynolds), [-]
%
% See also: af_tools.Airfoil, af_tools.xf2mat.
%
% <a href="https://gitlab.uliege.be/am-dept/matlab_airfoil_toolbox">Documentation (online)</a>
% TODO: make this class handle class, verify everything, simplfiy methods
% -------------------------------------------
% (c) Copyright 2022 University of Liege
% Author: Thomas Lambert <t.lambert@uliege.be>
% ULiege - Aeroelasticity and Experimental Aerodynamics
% MIT License
% Repo: https://gitlab.uliege.be/am-dept/matlab_airfoil_toolbox
% Issues: https://gitlab.uliege.be/am-dept/matlab_airfoil_toolbox/-/issues
% ----------------------------------------------------------------------------------------------
properties
reynolds (1, :) double {mustBeNonnegative} % Rynolds number, [-]
mach (1, :) double {mustBeNonnegative} % Mach number, [-]
nCrit (1, :) double {mustBeNonnegative} % nCrit number, [-]
aoa (:, :) double {mustBeReal} % Angles of attack, [rad]
cl (:, :) double {mustBeReal} % Lift coefficient, [-]
cd (:, :) double {mustBeReal} % Drag coefficient, [-]
cm (:, :) double {mustBeReal} % Moment coefficient, [-]
end
properties (SetAccess = private)
Ext = struct('aoa', [], 'cl', [], 'cd', [], 'cm', []) % Extended polar data
Stall = struct('aoa', [], 'cl', [], 'cd', []) % Stall point data
Zero = struct('aoa', [], 'cd', []) % Zero-lift point data
Lin = struct('slope', [], 'aoaRange', [], 'clRange', []) % Lift linear range data
end
% ----------------------------------------------------------------------------------------------
methods
function self = Polar(reynolds, aoa, c_l, c_d, c_m)
% POLAR Constructor for Polar object
% Instantiate a polar object using basic information. See the main class help for
% details about the constructor inputs.
%
% It is also possible to populate the properties of the object based on a saved polar
% using the Polar.loadpolar method.
%
% See also: af_tools.Polar.loadpolar
if nargin > 0
narginchk(3, 5);
self.reynolds = reynolds;
self.aoa = aoa;
self.cl = c_l;
if nargin >= 4
self.cd = c_d;
if nargin >= 5
self.cm = c_m;
end
end
end
end
% ---------------------------------------
function self = extendpolar(self)
% EXTENDPOLAR Extends the polar data over the full range of AOA ([-180, 180] deg)
%
% See also: af_tools.extendpolar.
[self.Ext.aoa, self.Ext.cl, self.Ext.cd] = af_tools.extendpolar(self);
end
% ---------------------------------------
function self = findstall(self)
% FINDSTALL Find the stall point of the polars
%
% See also: af_tools.findstall.
[self.Stall.aoa, self.Stall.cl, self.Stall.cd] = af_tools.findstall(self);
end
% ---------------------------------------
function self = findzerolift(self)
% FINDZEROLIFT Find the zero-lift angle and associated cd
%
% See also: af_tools.findzerolift.
[self.Zero.aoa, self.Zero.cd] = af_tools.findzerolift(self); end
% ---------------------------------------
function self = findcllinrange(self)
% FINDZEROLIFT Find the linear range of the cl and its slope
%
% See also: af_tools.findcllinearrange.
[self.Lin.clRange, self.Lin.aoaRange, self.Lin.slope] = ...
af_tools.findcllinearrange(self);
end
% ---------------------------------------
function plotpolars(self)
% PLOTPOLARS Plot the polars
%
% See also: af_tools.plotpolars.
af_tools.plotpolars(self);
end
% ---------------------------------------
function self = analyze(self)
% ANALYZE Get all useful information from the polar curves at once
%
% See also: af_tools.findstall, af_tools.findzerolift, af_tools.findcllinearrange.
self = findstall(self);
self = findzerolift(self);
self = findcllinrange(self);
end
% Interpolate coefficients based on AoAs and Reynolds
[cl, cd, cm] = getcoeffs(self, aoa, reynolds)
end
% ----------------------------------------------------------------------------------------------
methods (Static)
self = loadpolar(polarFile) % Load polar from file
end
% ----------------------------------------------------------------------------------------------
methods (Static)
self = polypolar(polyCl, polyCd) % Create polar using polynomial coefficients
end
end