On the stick-slip flow from slit and cylindrical dies of a Phan-Thien and Tanner fluid model. I. Steady state

2009 ◽  
Vol 21 (12) ◽  
pp. 123101 ◽  
Author(s):  
George Karapetsas ◽  
John Tsamopoulos
Keyword(s):  
Steady State ◽  
Fluid Model ◽  
Slip Flow ◽  
Stick Slip

scholarly journals A three-dimensional steady state thermal fluid model of jumbo ingot casting during electron beam re-melting of Ti–6Al–4V

2014 ◽  
Vol 38 (14) ◽  
pp. 3607-3623 ◽  
Author(s):  
X. Zhao ◽  
C. Reilly ◽  
L. Yao ◽  
D.M. Maijer ◽  
S.L. Cockcroft ◽  
...  
Keyword(s):  
Electron Beam ◽  
Steady State ◽  
Fluid Model ◽  
Three Dimensional ◽  
Ingot Casting

Experimental Investigation of Power Umbilical Damping

2017 ◽  
Author(s):  
Torfinn Ottesen
Keyword(s):  
Steady State ◽  
Energy Input ◽  
State Energy ◽  
Seawater Temperature ◽  
Structural Damping ◽  
Stick Slip ◽  
Slip Regime ◽  
Free Decay ◽  
Vortex Induced Vibrations ◽  
Slip Transition

Ocean currents may cause vortex induced vibrations (VIV) of deep-water umbilicals and cables. Since the VIV response may give significant contributions to the total fatigue damage it is important to know the structural damping for relevant curvature levels. A laboratory test has been performed on a 12.5 m long test specimen to determine the damping for a range of curvature levels that are in the vicinity of the stick-slip transition region. The energy input to maintain steady state oscillations with curvature amplitudes in the range 0.0002–0.001 m−1 was measured. The steady state energy input is consistent with damping ratios obtained using the free decay method. The structural damping depends on construction temperature and curvature and is less for typically low seawater temperature and low curvatures. The transition between the stick- and the slip regime is seen for typical seawater temperature.

A higher order slip flow of generalized Micropolar nanofluid with applications of motile microorganisms, nonlinear thermal radiation and activation energy

2021 ◽  
pp. 2150095
Author(s):  
Usman ◽  
M. Ijaz Khan ◽  
Sami Ullah Khan ◽  
Abuzar Ghaffari ◽  
Yu-Ming Chu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Radiation ◽  
Micropolar Fluid ◽  
Fluid Model ◽  
Slip Flow ◽  
Higher Order ◽  
Nonlinear Thermal Radiation ◽  
Coupled Equations ◽  
Flow Parameters ◽  
Micropolar Nanofluid

This communication aims to develop the thermal flow model for generalized micropolar nanofluid with insensitive applications of bioconvection, activation energy and nonlinear thermal radiation. The generalized micropolar fluid model is the extension of traditional micropolar fluid model with viscoelastic relations. The viscous nature of non-Newtonian micropolar material can be successfully predicted with help of this model. The motivating idea for considering the motile microorganisms is to control the nanoparticles suspension effectively. The higher order slip relations are incorporated to examine the bio-convective phenomenon. The simplified coupled equations in terms of non-dimensional variables are numerically treated with shooting scheme. The reliable graphical outcomes are presented for flow parameters governed to the transported problem. The flow pattern of each parameter is highlighted in view of viscous nature of micropolar fluid.

A steady-state fluid model of a rotating plasma

1981 ◽  
Vol 24 (3) ◽  
pp. 418 ◽  
Author(s):  
S. W. Simpson
Keyword(s):  
Steady State ◽  
Fluid Model

Asymptotic Impact Control of Hydraulic Actuators With Friction

2004 ◽  
Author(s):  
P. Sekhavat ◽  
N. Sepehri ◽  
Q. Wu
Keyword(s):  
Steady State ◽  
Nonlinear Control ◽  
Dry Friction ◽  
Position Control ◽  
Past Research ◽  
Hydraulic Actuator ◽  
Stick Slip ◽  
Hydraulic Actuators ◽  
Control Scheme ◽  
Control Schemes

The focus of this work is stabilization of hydraulic actuators during the transition from free motion to constraint motion and regulating the intermediate impacts that could drive the system unstable. In our past research, we introduced Lyapunov-based nonlinear control schemes capable of fulfilling the above goal by resting the implement on the surface of the environment before starting the sustained-contact motion. The hydraulic actuator’s stick-slip friction effect was, however, either not included in the analysis or not compensated by the control action. In this paper, the application of our previously introduced friction compensating position control scheme is extended to impact regulation of a hydraulic actuator. Theoretical solution and stability analyses as well as actual experiments prove that such control scheme is also effective for asymptotic impact control (with no position steady-state error) of hydraulic actuators in the presence of actuator’s dry friction.

Performance of Lightly Loaded Gas Journal Bearings in the Slip-Flow and Turbulent-Flow Regimes

1968 ◽  
Vol 10 (4) ◽  
pp. 363-366
Author(s):  
M. D. Wood
Keyword(s):  
Steady State ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Reynolds Equation ◽  
Dynamic Performance ◽  
Slip Flow ◽  
Flow Regimes ◽  
Journal Bearings ◽  
Performance Parameters ◽  
Existing Data

The note compares recently published versions of the governing gas film equations for slip-flow and turbulent flow with Reynolds equation for laminar flow. The comparison shows how approximate values of steady-state and dynamic performance parameters may be deduced for the new conditions from existing data.

Static characteristics of hydrostatic doubled-layered porous journal bearings with slip flow including additives percolation into pores under coupled stress lubrication

2017 ◽  
Vol 232 (8) ◽  
pp. 927-939 ◽  
Author(s):  
Shitendu Some ◽  
Sisir K Guha
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Slip Flow ◽  
Journal Bearings ◽  
Static Characteristics ◽  
Governing Equations ◽  
Modified Reynolds Equation ◽  
Film Interface ◽  
Coupled Stress ◽  
Steady State Performance

A theoretical analysis of the steady-state characteristics of finite hydrostatic double-layered porous journal bearings dealing with the effects of slip flow at the fine porous layer–film interface and percolation of additives into pores under the coupled stress fluid lubrication is presented. Based on the Beavers–Joseph’s criterion for slip flow, the modified Reynolds equation applicable to finite porous journal bearings lubricated with coupled stress fluids have been derived. The governing equations for flow in the coarse and fine layers of porous medium incorporating the percolation of polar additives of lubricant and the modified Reynolds equation are solved simultaneously using finite difference method satisfying appropriate boundary conditions to obtain the steady-state performance characteristics for various parameter namely percolation factor, slip coefficient, bearing feeding parameter, coupled stress parameter, and eccentricity ratio. The results are exhibited in the form of graphs, which may be useful for design of such bearing.

Analytical Investigation of Hopf Bifurcations Occurring in a 1DOF Sliding-Friction Oscillator With Application to Disc-Brake Vibrations

2005 ◽  
Author(s):  
Hartmut Hetzler ◽  
Wolfgang Seemann ◽  
Daniel Schwarzer
Keyword(s):  
Fixed Point ◽  
Steady State ◽  
Limit Cycle ◽  
Relative Velocity ◽  
Sliding Friction ◽  
Analytical Investigation ◽  
Stable Region ◽  
Stable Steady State ◽  
Disc Brake ◽  
Stick Slip

This article deals with analytical investigations on stability and bifurcations due to declining dry friction characteristics in the sliding domain of a simple disc-brake model, which is commonly referred to as “mass-on-a-belt”-oscillator. Sliding friction is described in the sense of Coulomb as proportional to the normal force, but with a friction coefficient μS which depends on the relative velocity. For many common friction models this latter dependence on the relative velocity can be described by exponential functions. For such a characteristic the stability and bifurcation behavior is discussed. It is shown, that the system can undergo a subcritical Hopf-bifurcation from an unstable steady-state fixed point to an unstable limit cycle, which separates the basins of the stable steady-state fixed point and the self sustained stick-slip limit cycle. Therefore, only a local examination of the eigenvalues at the steady-state, as is the classical ansatz when investigating conditions for the onset of friction-induced vibrations, may not give the whole picture, since the stable region around the steady state fixed point may be rather small. The analytical results are verified by numerical simulations. Parameter values are chosen for a model which corresponds to a conventional disc-brake.

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