Improvement in the slotted wall boundary condition by numerical methods

The constant coefficient in the classical slotted wall boundary condition is expressed as a line integral of the slot-induced, rapidly varying velocity. Aerodynamic panel methods which employ a vector continuous loading concept in order to minimize panel leakage are used to compute the inviscid flow through periodic slots, from which the slotted wall coefficient is evaluated by means of numerical integration. This approach is expected to yield improved results, inasmuch as no idealizations in slat geometry are required. For the first time, the method affords the capability to obtain insight into the effects upon the slotted wall coefficient of minor alterations in slat shape, such as geometry changes which leave invariant the openness and thickness ratios. The coefficient is numerically evaluated for slat shapes typical of test section design.