Small-perturbation propagation in a system consisting of a preliminarily stressed incompressible cylinder and fluid

1980 ◽  
Vol 16 (6) ◽  
pp. 487-491
Author(s):  
A. M. Bagno

2010 ◽  
Vol 53 (2) ◽  
pp. 141-148
Author(s):  
R. Yu. Amenzade ◽  
E. T. Kiyasbeili ◽  
A. A. Nasirzade


Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 183
Author(s):  
Yongjie Liu ◽  
Yu Jiang ◽  
Hengnian Li ◽  
Hui Zhang

This paper intends to show some special types of orbits around Jupiter based on the mean element theory, including stationary orbits, sun-synchronous orbits, orbits at the critical inclination, and repeating ground track orbits. A gravity model concerning only the perturbations of J2 and J4 terms is used here. Compared with special orbits around the Earth, the orbit dynamics differ greatly: (1) There do not exist longitude drifts on stationary orbits due to non-spherical gravity since only J2 and J4 terms are taken into account in the gravity model. All points on stationary orbits are degenerate equilibrium points. Moreover, the satellite will oscillate in the radial and North-South directions after a sufficiently small perturbation of stationary orbits. (2) The inclinations of sun-synchronous orbits are always bigger than 90 degrees, but smaller than those for satellites around the Earth. (3) The critical inclinations are no-longer independent of the semi-major axis and eccentricity of the orbits. The results show that if the eccentricity is small, the critical inclinations will decrease as the altitudes of orbits increase; if the eccentricity is larger, the critical inclinations will increase as the altitudes of orbits increase. (4) The inclinations of repeating ground track orbits are monotonically increasing rapidly with respect to the altitudes of orbits.



Author(s):  
Jannette B. Frandsen ◽  
Alistair G. L. Borthwick

Nonlinear effects of standing wave motions in fixed and vertically excited tanks are numerically investigated. The present fully nonlinear model analyses two-dimensional waves in stable and unstable regions of the free-surface flow. Numerical solutions of the governing nonlinear potential flow equations are obtained using a finite-difference time-stepping scheme on adaptively mapped grids. A σ-transformation in the vertical direction that stretches directly between the free-surface and bed boundary is applied to map the moving free surface physical domain onto a fixed computational domain. A horizontal linear mapping is also applied, so that the resulting computational domain is rectangular, and consists of unit square cells. The small-amplitude free-surface predictions in the fixed and vertically excited tanks compare well with 2nd order small perturbation theory. For stable steep waves in the vertically excited tank, the free-surface exhibits nonlinear behaviour. Parametric resonance is evident in the instability zones, as the amplitudes grow exponentially, even for small forcing amplitudes. For steep initial amplitudes the predictions differ considerably from the small perturbation theory solution, demonstrating the importance of nonlinear effects. The present numerical model provides a simple way of simulating steep non-breaking waves. It is computationally quick and accurate, and there is no need for free surface smoothing because of the σ-transformation.



2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Stefan Balint ◽  
Agneta M. Balint

This paper considers the stability of constant solutions to the 1D Euler equation. The idea is to investigate the effect of different function spaces on the well-posedness and stability of the null solution of the 1D linearized Euler equations. It is shown that the mathematical tools and results depend on the meaning of the concepts “perturbation,” “small perturbation,” “solution of the propagation problem,” and “small solution, that is, solution close to zero,” which are specific for each function space.



2017 ◽  
Vol 22 (4) ◽  
pp. 297-304 ◽  
Author(s):  
Ming Jin ◽  
Nicole DeHoratius ◽  
Glen Schmidt

Purpose The popular “beer game” illustrates the bullwhip effect where a small perturbation in downstream demand can create wild swings in upstream product flows. The purpose of this paper is to present a methodical framework to measure the bullwhip effect and evaluate its impact. Design/methodology/approach This paper illustrates a framework using SKU-level data from an industry-leading manufacturer, its distributors, end-users and suppliers. Findings Firms benefit from tracking multiple intra-firm bullwhips and from tracking bullwhips pertinent to specific products, specific suppliers and specific customers. The framework presented in this paper enables managers to pinpoint bullwhip sources and mitigate bullwhip effects. Research limitations/implications This paper presents a framework for methodically measuring and tracking intra-firm and inter-firm bullwhips. Practical implications A disconnect exists between what is known and taught regarding the bullwhip effect and how it is actually tracked and managed in practice. This paper aims to reduce this gap. For the various products analyzed herein, the authors show how using this framework has the potential to reduce delivered product cost by 2 to 15 per cent. Social implications Properly managing the bullwhip leads to lower inventories and potentially lower product prices while simultaneously increasing firm profits. Originality/value This paper presents a novel approach to systematically tracking intra-firm bullwhips along with bullwhips specific to a given supplier or customer.



2017 ◽  
Vol 31 (34) ◽  
pp. 1750324 ◽  
Author(s):  
Hong Xiao ◽  
Hai-Jun Huang ◽  
Tie-Qiao Tang

Electric vehicle (EV) has become a potential traffic tool, which has attracted researchers to explore various traffic phenomena caused by EV (e.g. congestion, electricity consumption, etc.). In this paper, we study the energy consumption (including the fuel consumption and the electricity consumption) and emissions of heterogeneous traffic flow (that consists of the traditional vehicle (TV) and EV) under three traffic situations (i.e. uniform flow, shock and rarefaction waves, and a small perturbation) from the perspective of macro traffic flow. The numerical results show that the proportion of electric vehicular flow has great effects on the TV’s fuel consumption and emissions and the EV’s electricity consumption, i.e. the fuel consumption and emissions decrease while the electricity consumption increases with the increase of the proportion of electric vehicular flow. The results can help us better understand the energy consumption and emissions of the heterogeneous traffic flow consisting of TV and EV.



Sign in / Sign up

Export Citation Format

Share Document