spanwise_interpolation
Returns the interpolation weights and indices of said weights for a span wise interpolation. The indices refer to column indices of a row vector containing the gust disturbance at each chordwise control point.
This is used in non-span uniform gusts with multiple inputs, where each set of chordwise control points in the state vector corresponds to one gust (i.e. its time history).
The interpolation is performed as follows.
For an arbitrary point within a grid delimited by (0, 0)
, (0, 1)
, (1, 0)
and (1, 1)
, the velocity
at a given point is:
where \(\alpha_1 = \frac{y - y_0}{y_{1} - y_{0}}\) and \(\alpha_0 = \frac{y_1-y}{y_1-y_0}\).
The velocities \(u_1\) and \(u_0\) are at the current chordwise point, thus translating into
where \(\beta_{11} = \frac{x - x_0}{x_1 - x_0}\) and the rest follow a similar pattern.
The resulting interpolation scheme gives
The indices returned as part of the output correspond to the column indices above to match with the corresponding interpolation control points.
- param y_vertex:
y (span) coordinate of point
- type y_vertex:
np.float
- param span_loc:
Domain of y-coordinates
- type span_loc:
np.array
- param x_vertex:
x (chord) coordinate of point
- type x_vertex:
np.float
- param x_domain:
Domain of x coordinates
- type x_domain:
np.array
- returns:
- 2-tuple containing i) the 4-array of interpolation weights and ii) the 4-array of column
indicies to place such weights.
- rtype:
tuple