ATWO-DIMENSIONAL numerical solution using an inviscid time marching method has been compared with interferometric data obtained from image plane holograms. This has been done over the whole blade profile including the trailing edge shock region, but a particularly detailed analysis has been made of the leading edge. The data obtained show isodensity/iso-Mach contours (AM=0.03), with a spacing of typically 50 /mi between them. It was found that a highly refined grid size of similar resolution was required to compute an accurate solution. Contents Description of Flow The two-dimensional airfoil section which was based upon a NACA 0010-34 profile1 was mounted at zero incidence in the center of the tunnel on two supports from below. These were located within the tunnel flow, causing a 12% blockage of the throat area beneath the blade. It may be thought that such a large blockage would generate three-dimensional effects; previous oil flow and pressure measurements show this not to be the case.1 They also show that despite a 5-mmthick sidewall boundary layer the flow on the upper surface of the blade is two-dimensional for 90% of its span. As a result of the partial blockage of the blade at the leading edge, the stagnation point has moved toward the pressure surface. The flow is seen to accelerate around the leading edge up to a maximum speed of M=1.25 (Fig. 1). This can be compared with the computed flow solutions shown in Figs. 2-4. The flow remains attached around the leading edge and subsequently decelerated to a minimum Mach number of 1.06 at 10% of the blade chord. The suction surface of the blade then behaves in a more conventional manner, the supersonic flow being accelerated by the convex surface of the blade profile up to M= 1.26. It is also noted that the boundary-layer thickness at the trailing edge is 2 mm. This thickness has not been taken into account in the inviscid calculations. Optical System The optical system used in this experiment was similar to that applied previously2 to turbine cascade, image plane holography. The interferometric fringes formed in the