No abstract

The approach consists of comparing inlet operating requirements with estimated inlet separation characteristics to identify the most critical inlet operating condition. This critical condition is taken to be the design point and is defined by the values of inlet mass flow, free stream velocity, and inlet angle of attack. Optimum flow distributions on the inlet surface are determined to be a high, flat top Mach number distribution on the inlet lip to turn the flow quickly into the inlet and a low, flat bottom skin friction distribution on the diffuser wall to diffuse the flow rapidly and efficiently to the velocity required at the fan face. These optimum distributions are then modified to achieve other desirable flow characteristics. Example applications are given. Extension of the method is suggested.

o f HTS for a e r o n a u t i c s i n d i c a t e s t h a t s i g n i f i c a n t b e n e f i t s may be r e a l i z e d t h r o u g h t h e development and i m p l e m e n t a t i o n o f these newly d i s c o v e r e d m a t e r i a l s .-A p p l i c a t i o n s o f h i g h -t e m p e r a t u r e superconductors ( c u r r e n t l y s u b s t a n t i a t e d a t i n g subsonic and s u p e r s o n i c t r a n s p o r t s , h y p e r s o n i c a i r c r a f t , V/STOL a i r c r a f t , ' r o t o r c r a f t , and s o l a r , m i crowave and 1 a s e r powered a i r c r a f t .I n t h i s paper, we s h a l l i n t r o d u c e and d e s c r i b e p a r t i c u l a r a p p l i c a t i o n s and p o t e n t i a l b e n e f i t s o f h i g h -t e m p e r a t u r e superconductors as r e l a t e d t o a e r o n a u t i c s a n d / o r a e r o n a u t i c a l systems.

The paper provides a theoretical description of the development of the boundary layer on the lip and diffuser surface of a subsonic inlet at arbitrary operating conditions of mass flow rate, freestream velocity, and incident angle. Both laminar separation on the lip and turbulent separation in the diffuser are discussed. The agreement of the theoretical results with model experimental data illustrates the capability of the theory to predict separation location. The effects of throat Mach number, inlet size, and surface roughness on boundary-layer development and separation are illustrated. NomenclatureC f = local skin friction coefficient (ratio of wail shear stress to dynamic pressure at edge of boundary layer) D e = diffuser exit diameter, cm D h = highlight diameter Anax = maximum diameter D t = throat diameter H = shape factor, ratio of boundary-layer displacement to momentum thickness L = total length of inlet L e = length of centerbody M = local Mach number M T = average one-dimensional throat Mach number based on inlet weight flow rate and geometric throat area M 0 = freestream Mach number q 2 12 = kinetic energy turbulence R = Reynolds number RIJ = Reynolds stress tensor 5 = surface distance from inlet highlight u/U e = ratio of velocity in the boundary layer to velocity at the edge of the boundary layer y = distance in the boundary layer normal to the inlet surface, cm a. = inlet incidence angle, deg 6 = boundary-layer thickness, cm d k = kinematic displacement thickness e m = eddy viscosity v = kinematic viscosity 6 = momentum thickness