Alleviation of pitch-up on delta wings using distributed porosity

An experimental investigation was undertaken to determine the effectiveness of distributed surface porosity for the alleviation of pitch-up on a delta wing. Tests were undertaken using a 65 degrees sweep delta wing with distr ibuted porosity evaluated at various locations on the wing. Force balance, on and off surface flow visualisation and flow field surveys using a multi- hole probe were undertaken. The data shows that distributed porosity applie d along the wing leading edge at the apex is effective in eliminating pitch -up whilst incurring a minimal performance cost. Trailing edge porosity gen erally degraded performance.