a

p 1 / S 6 0 An investigation has been made i n the Langley l5-inch hypersonic flow apparatus t o es tab l i sh the extent and magnitude of t he separation-induced pres-sure d i s t r ibu t ion on f la t surfaces ahead of small-span ramps and t o evaluate t h e usefulness of two-dimensional separation theory f o r correlat ing and pre-d ic t ing the charac te r i s t ics of laminar separation i n three-dimensional flow. Pressure d is t r ibu t ions were obtained on a f l a t p l a t e with an aft-mounted ramp a t a Mach number of 10.03 and Reynolds numbers per inch of approximately 1.27 X 16 and 1.53 x 105. and the r a t i o of the ramp span t o the ramp chord ( the ramp aspect r a t i o) was varied from 2 t o 4 by varying the ramp span. The ramp deflection angle was varied from Oo t o 40° The experimental r e s u l t s indicate t h a t increasing the def lect ion angle of a f ini te-span ramp from loo t o 400 r e s u l t s i n increases i n the length of t he separated region along the model center l i n e and i n the magnitude of t he pres