68 research outputs found
Instructions for the use of the FORTRAN 4 program COMPT
The programming manual for the program COMPT which computes the non-steady two dimensional flow field resulting from the interaction of two successive blade rows is presented. The manual is designed to provide guidance in running the program and a brief description of some of the numerical details. A brief review of the main features of the program is given
Unsteady flow through compressor stages
The application of the nonsteady Lax-Wendroff technique to problems with asymptotically periodic solution which offers a potentially powerful method for the investigation of the interaction of rotating and stationary blade rows in turbomachinery is reported. A technique for specifying boundary conditions with phase lag was developed to accomplish this. A complete nonlinear analysis is carried out numerically to determine the entire flow field without recourse to the assumption of small disturbances of linear equations which underlie the previous acoustic theories. The result, obtained for the case of equal number of rotor and stator blades shows that transonic flow can be handled without difficulty. In addition, the program is not limited with regard to blade thickness, camber or loading. Extension of this method to incorporate viscous wakes and to analysis of fully three dimensional configuration is feasible, and would greatly expand its utility in practical applications
Computation of unsteady transonic flows through rotating and stationary cascades. 1: Method of analysis
A numerical method of solution of the inviscid, compressible, two-dimensional unsteady flow on a blade-to-blade stream surface through a stage (rotor and stator) or a single blade row of an axial flow compressor or fan is described. A cyclic procedure has been developed for representation of adjacent blade-to-blade passages which asymptotically achieves the correct phase between all passages of a stage. A shock-capturing finite difference method is employed in the interior of the passage, and a method of characteristics technique is used at the boundaries. The blade slipstreams form two of the passage boundaries and are treated as moving contact surfaces capable of supporting jumps in entropy and tangential velocity. The Kutta condition is imposed by requiring the slipstreams to originate at the trailing edges, which are assumed to be sharp. Results are presented for several transonic fan rotors and compared with available experimental data, consisting of holographic observations of shock structure and pressure contour maps. A subcritical stator solution is also compared with results from a relaxation method. Finally, a periodic solution for a stage consisting of 44 rotor blades and 46 stator blades is discussed
Computation of unsteady transonic flows through rotating and stationary cascades. 2: User's guide to FORTRAN program B2DATL
Documentation for the FORTRAN program B2DATL is provided. The program input, output, and operational procedures are described; a dictionary of the principal FORTRAN variables is provided; the function of all subroutines; is outlined and flow charts of the principal subroutines and the main program are presented
Time-dependent transonic flow solutions for axial turbomachinery
Three-dimensional unsteady transonic flow through an axial turbomachine stage is described in terms of a pair of two-dimensional formulations pertaining to orthogonal surfaces, namely, a blade-to-blade surface and a hub-to-casing surface. The resulting systems of nonlinear, inviscid, compressible equations of motion are solved by an explicit finite-difference technique. The blade-to-blade program includes the periodic interaction between rotor and stator blade rows. Treatment of the boundary conditions and of the blade slipstream motion by a characteristic type procedure is discussed in detail. Harmonic analysis of the acoustic far field produced by the blade row interaction, including an arbitrary initial transient, is outlined. Results from the blade-to-blade program are compared with experimental measurements of the rotating pressure field at the tip of a high-speed fan. The hub-to-casing program determines circumferentially averaged flow properties on a meridional plane. Blade row interactions are neglected in this formulation, but the force distributions over the entire blade surface for both the rotor and stator are obtained. Results from the hub-to-casing program are compared with a relaxation method solution for a subsonic rotor. Results are also presented for a quiet fan stage which includes transonic flow in both the rotor and stator and a normal shock in the stator
Prescription of potentially inappropriate medications among older people with intellectual disability: a register study
Bericht vom XXIX. International Congress of Ophthalmology — The World Meeting of Ophthalmologists, 21.–25. April 2002, Sydney — Australien
Erratum zu: Ein neues Retinnometer (Heine Lambda 100) im Vergleich mit dem Interferometer (Interzeag IRAS 760) bei der präoperativen evaluierung der Katarakt-Patienten
Orbits for five southern visual binaries
First orbits have been calculated for the visual binaries WDS 00090–5400,
01061–4643, 05248–5219 and 08447–5443 (Alzner & Argyle [CITE]; Argyle & Alzner
[CITE]). The current period for the orbit of (Wierzbinski
[CITE]) is too short to represent recent observations. The period has been lengthened
to 450 years (Alzner & Argyle [CITE]). For 00090–5400 the period is 221 years with
a moderate eccentricity; 01061–4643 is currently near periastron but is underobserved;
05248–5219 has passed periastron but there have been no observations since 1993.
The visual component of WDS 08447–5443 (= δ Vel), which is not the
same as the eclipsing component recently discovered by Otero ([CITE]),
has an unexpectedly short period
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