AN EXTRAPOLATION METHOD FOR ESTIMATING STEADY-FLOW VISCOSITY AND STEADY STATE COMPLIANCE FROM CREEP DATA

1963 ◽  
Vol 67 (5) ◽  
pp. 1152-1152 ◽  
Author(s):  
Kazuhiko Ninomiya
Keyword(s):  
Steady State ◽  
Steady Flow ◽  
Extrapolation Method ◽  
Creep Data ◽  
State Compliance

Relaxation of Compression Springs at High Temperatures

1970 ◽  
Vol 92 (3) ◽  
pp. 627-632
Author(s):  
M. J. Siegel ◽  
D. P. Athans
Keyword(s):  
Stainless Steel ◽  
Steady State ◽  
Stress Relaxation ◽  
Operating Temperature ◽  
Transient Creep ◽  
Tensile Creep ◽  
Creep Data ◽  
Limited Life ◽  
Compression Springs ◽  
Design Stress

An analysis is developed to determine the relaxation of cylindrical compression springs at temperatures where creep is predominantly steady state and the effect of transient creep and anelastic strain is small. Springs which operate under these conditions must be designed for limited life. Equations are derived which predict the relaxation of springs directly from tensile creep data for various materials. Using creep data for 18-8 stainless steel and Inconel-X, families of design curves are presented which give the time-temperature initial-stress relationships for various stress-relaxation ratios. These curves are useful in selecting an initial design stress for a specific operating temperature.

Aeroelasticity at Reversed Flow Conditions: Part 1—Numerical and Experimental Investigations of a Compressor Cascade With Controlled Vibration

2011 ◽  
Author(s):  
Harald Schoenenborn ◽  
Virginie Chenaux ◽  
Peter Ott
Keyword(s):  
Steady State ◽  
Flow Field ◽  
Unsteady Flow ◽  
Steady Flow ◽  
Experimental Investigations ◽  
Blade Surface ◽  
Flow Conditions ◽  
Steady State Flow ◽  
Reversed Flow ◽  
Blow Down

The prediction of flutter and forced response at normal flow conditions has become a standard procedure during the design of compressor airfoils. But at severe off-design conditions, the flow field becomes very complex, especially during the surge blow-down phase where reversed flow conditions occur. The correct prediction of the unsteady pressures and the resulting aerodynamic excitation or damping at these conditions remains an extremely challenging task. In the first part of the paper, basic investigations for these flow conditions are presented. Aeroelastic calculations during compressor surge are shown in the second part. Experimental investigations were performed in the Annular Test Facility for non-rotating cascades at EPF Lausanne. The test cascade was exposed to flow conditions as expected during the surge blow-down phase which is characterized by large separation regions. Measurements of the steady-state flow conditions on the blade surface, at the outer wall, upstream and downstream of the cascade provided detailed information about the steady flow conditions. The cascade was then subjected to controlled vibration of the blades with constant amplitudes and inter-blade phase angles. Unsteady pressure measurements on the blade surface and at the casing wall provided information about the resulting unsteady flow conditions. Analytical CFD calculations were performed. The steady flow field was calculated using a RANS code. Based on the steady-state flow field, unsteady calculations applying a linearized code were carried out. The agreement between measurements and calculations shows that the steady flow as well as the unsteady flow phenomena can be predicted quantitatively. In addition, knowing the blade vibration mode shape, which in this case is a torsion mode, the aerodynamic damping can be determined for the corresponding flow conditions.

scholarly journals Advection and dispersion of bed load tracers

2018 ◽  
Vol 6 (2) ◽  
pp. 389-399 ◽  
Author(s):  
Eric Lajeunesse ◽  
Olivier Devauchelle ◽  
François James
Keyword(s):  
Steady State ◽  
Steady Flow ◽  
Constant Velocity ◽  
Transport Rate ◽  
Bed Load ◽  
Deposition Model ◽  
Advection Diffusion ◽  
Maximum Value ◽  
Load Transport ◽  
Bed Load Transport

Abstract. We use the erosion–deposition model introduced by Charru et al. (2004) to numerically simulate the evolution of a plume of bed load tracers entrained by a steady flow. In this model, the propagation of the plume results from the stochastic exchange of particles between the bed and the bed load layer. We find a transition between two asymptotic regimes. The tracers, initially at rest, are gradually set into motion by the flow. During this entrainment regime, the plume is strongly skewed in the direction of propagation and continuously accelerates while spreading nonlinearly. With time, the skewness of the plume eventually reaches a maximum value before decreasing. This marks the transition to an advection–diffusion regime in which the plume becomes increasingly symmetrical, spreads linearly, and advances at constant velocity. We analytically derive the expressions of the position, the variance, and the skewness of the plume and investigate their asymptotic regimes. Our model assumes steady state. In the field, however, bed load transport is intermittent. We show that the asymptotic regimes become insensitive to this intermittency when expressed in terms of the distance traveled by the plume. If this finding applies to the field, it might provide an estimate for the average bed load transport rate.

scholarly journals Viscosity and Steady-State Compliance of Multi-Branched Star Polystyrenes

1986 ◽  
Vol 18 (4) ◽  
pp. 337-346 ◽  
Author(s):  
Yasuhiko Ohta ◽  
Toshiro Masuda ◽  
Shigeharu Onogi
Keyword(s):  
Steady State ◽  
State Compliance

The Steady-State Compliance of Dilute Polymer Solutions

1966 ◽  
Vol 70 (9) ◽  
pp. 2714-2719 ◽  
Author(s):  
Larry A. Holmes ◽  
Kazuhiko Ninomiya ◽  
John D. Ferry
Keyword(s):  
Steady State ◽  
Polymer Solutions ◽  
Dilute Polymer Solutions ◽  
State Compliance

THE FLOW OF HEAT THROUGH PLATES

1932 ◽  
Vol 6 (6) ◽  
pp. 577-583 ◽  
Author(s):  
R. Ruedy
Keyword(s):  
Steady State ◽  
Steady Flow ◽  
Finite Thickness ◽  
Theta Functions ◽  
Boundary Plane ◽  
Constant Level ◽  
The Other ◽  
Half Cycle ◽  
Uniform Temperature ◽  
Higher Temperature

The speed is calculated with which the steady flow of heat is established in a slab of uniform temperature after one boundary plane has been suddenly brought to a higher temperature, or when the temperature of both planes is changed. In both cases the flow of heat may be expressed by means of simple theta functions, and the law of approach to the steady state may be used for determining the diffusivity of the material. When one boundary plane undergoes sinusoidal variations in temperature while the other is maintained at a constant level, a finite thickness is found for which, in the steady state, the heat flowing in or out during one half-cycle reaches its highest value.

Sign in / Sign up

Export Citation Format

Share Document