Patent ID: 7685713

Claim:
A method of designing adjacent transonic airfoils to minimize downstream shock induced flowfield disturbance in an engine having a rotational axis, each transonic airfoil having an adjacent airfoil, and further having a pressure surface, a suction surface, a predetermined airfoil exit mach number, an exit flow angle, a pressure side trailing edge wedge angle, a suction side trailing edge wedge angle, and a suction side throat angle, the method comprising the steps of: selecting an airfoil exit deviation angle, the airfoil exit deviation angle having a magnitude; determining a combined shock induced flowfield disturbance at a position that corresponds to a leading edge of a downstream airfoil, the combined shock induced flowfield disturbance resulting, at least in part, from a suction side shock and a reflected shock, the suction side shock being a shock that emanates from the airfoil trailing edge suction side, the reflected shock resulting from a cross passage shock that emanates from the airfoil trailing edge pressure side and reflects off an adjacent airfoil suction side; and varying the airfoil exit deviation angle until the combined shock induced flowfield disturbance at the position that corresponds to a leading edge of a downstream airfoil is minimized, wherein: a line that bisects the pressure surface and the suction surface defines a trailing edge metal line, an angle between flow streamlines downstream of the airfoil trailing edge and a line that extends parallel to the engine rotational axis defines an airfoil exit flow angle, an angle between the trailing edge metal line and the line that extends parallel to the engine rotational axis defines a trailing edge metal angle, an angle between the trailing edge metal angle and the airfoil exit flow angle defines the airfoil exit deviation angle, and the step of determining the combined shock induced flow field disturbance comprises: determining a peak-to-peak amplitude of a suction shock static pressure variation at the position that corresponds to a leading edge of a downstream airfoil, the suction shock static pressure variation resulting from the suction side shock; determining a peak-to-peak amplitude of a reflected shock static pressure variation at the position that corresponds to a leading edge of a downstream airfoil, the reflected shock static pressure variation resulting from the reflected shock; and comparing the peak-to-peak amplitude of the suction shock static pressure variation and the reflected shock static variation to determine which is greater.