Region Of Exit Research Articles

Turbulence Characteristics in the Annulus-Wall Boundary Layer and Wake Mixing Region of a Compressor Rotor Exit

The flow at the exit of a turbomachinery rotor near the annulus wall is three-dimensional with a varying degree of turbulence and nonisotropic characteristics. The characteristics of the turbulence vary considerably with radial and axial location, blade loading, Reynolds number, free-stream turbulence, and the rotor blade geometry. This paper is concerned with the turbulence properties near the annulus wall region of a moderately loaded compressor blade. The variation of the streamwise, normal, and radial intensities as well as the stresses across the wake, its profile and decay characteristics, were determined with a tri-axial hot-wire probe in the stationary frame of reference. The turbulence characteristics in the annulus-wall region of the rotor exit were found to be highly complex due to the interaction of the blade wake and the annulus wall.

ETIOLOGY OF OPTOCHIASMATIC ARACHNOIDITIS

IN SPITE of the increasing number of cases of optochiasmatic arachnoiditis reported in the literature and the general recognition of such a condition at operation, the etiologic agent in many instances remains obscure. 1 Optochiasmatic arachnoiditis is defined as an abnormal thickening of the arachnoid in the region of the optic nerves and the optic chiasm. The process frequently extends to neighboring structures, in particular to the region of exit of both third nerves, and may reach the caudal portion of the pons, in which case the term basilar arachnoiditis is more appropriate. In the older literature the same condition goes under the name of chronic basilar meningitis. Fine films of arachnoid are normally present, forming the chiasmatic cistern. In cases of optochiasmatic arachnoiditis there are solid bands of the arachnoid, which insert either on the optic nerves or on adjacent structures, such as blood vessels. Or there are aprons