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Inertia

About: Inertia is a research topic. Over the lifetime, 12006 publications have been published within this topic receiving 164291 citations.


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Journal ArticleDOI
TL;DR: In this paper, the orientation of an ellipsoid falling in a viscoelastic fluid is studied by methods of perturbation theory and the original problem is split into three canonical problems: the zeroth-order Stokes problem for a translating ellipssoid and two first-order problems, one for inertia and one for second-order rheology.
Abstract: The orientation of an ellipsoid falling in a viscoelastic fluid is studied by methods of perturbation theory. For small fall velocity, the fluid's rheology is described by a second-order fluid model. The solution of the problem can be expressed by a dual expansion in two small parameters: the Reynolds number representing the inertial effect and the Weissenberg number representing the effect of the non-Newtonian stress. Then the original problem is split into three canonical problems: the zeroth-order Stokes problem for a translating ellipsoid and two first-order problems, one for inertia and one for second-order rheology. A Stokes operator is inverted in each of the three cases. The problems are solved numerically on a three-dimensional domain by a finite element method with fictitious domains, and the force and torque on the body are evaluated. The results show that the signs of the perturbation pressure and velocity around the particle for inertia are reversed by viscoelasticity. The torques are also of opposite sign: inertia turns the major axis of the ellipsoid perpendicular to the fall direction; normal stresses turn the major axis parallel to the fall. The competition of these two effects gives rise to an equilibrium tilt angle between 0° and 90° which the settling ellipsoid would eventually assume. The equilibrium tilt angle is a function of the elasticity number, which is the ratio of the Weissenberg number and the Reynolds number. Since this ratio is independent of the fall velocity, the perturbation results do not explain the sudden turning of a long body which occurs when a critical fall velocity is exceeded. This is not surprising because the theory is valid only for slow sedimentation. However, the results do seem to agree qualitatively with ‘shape tilting’ observed at low fall velocities.

40 citations

Proceedings ArticleDOI
07 May 1995
TL;DR: A dynamic transfer function for an isometric joystick is described which amplifies changes in the applied force to increase rcsponsivcncss without loss of control.
Abstract: In-keyboard isometric joysticks can give better pcrforrnancc than mice for mixed typing/pointing tasks. The continuing challcngc is to improve such devices to the point that they arc preferable even for pure pointing tasks. Previous work has improved joystick performance by considering user perception and motor skills. This paper considers the dynamics of the pointing operation. A dynamic transfer function for an isometric joystick is described which amplifies changes in the applied force to increase rcsponsivcncss without loss of control. User tests show a 7.8k3.5°/0 pcrfonnancc improvement over a standard non-dynamic joystick. This feature has been incorporated into the TrackPoint 111from IBM.

40 citations

Journal ArticleDOI
TL;DR: In this article, a dual-cavity coat-hanger die was designed to simulate polymeric fluid flow inside the die and the flow patterns in the outer cavity were computed by the finite element method so that the appearance of an undesirable vortex could be predicted.
Abstract: A method for the design and analysis of a dual-cavity coat-hanger die is presented in this paper. A macroscopic material balance and a microscopic flow analysis using the finite element method are combined to simulate polymeric fluid flow inside the die. Leonard's macroscopic procedure was adopted to include inertial, gravitational, and viscous effects, and the finite element method was then applied to estimate the contributions of inertial and viscous terms. In addition, the flow patterns in the outer cavity were computed by the finite element method so that the appearance of an undesirable vortex could be predicted. The residence time distributions for flow in the die were approximated by a simple, statistical approach. It was found through a case study that a dual-cavity coathanger die can effectively reduce the flow non-uniformities caused by fluid inertia and viscosity variations.

40 citations

Proceedings ArticleDOI
24 Dec 2012
TL;DR: It is shown that the use of a flywheel with a calculated rotational inertia using the proposed method can be sufficient in emulating vehicle inertia effect on a test bench.
Abstract: This paper provides an easy yet accurate approach for estimating vehicle inertia for the purpose of simulating the effect of vehicle inertia using a large flywheel. The method used to properly map the linear inertia of a vehicle to an equivalent rotational inertia is described in detail and an expression for equivalent rotational inertia of a vehicle is derived analytically using two different approaches considering kinetic energy of a moving mass in the linear and rotational context and vehicle dynamic equations. A MATLAB/Simulink model of a test bench consisting of a torque actuator connected to a large flywheel is used to emulate the effect of vehicle inertia. Using this model, the dynamic inertia effect of an electric vehicle on its traction motor is illustrated for two standard drive cycles. The results obtained from simulation are validated by ADVISOR to confirm the effectiveness of the proposed method in estimating vehicle inertia and it is shown that the use of a flywheel with a calculated rotational inertia using the proposed method can be sufficient in emulating vehicle inertia effect on a test bench.

40 citations

Journal ArticleDOI
TL;DR: The original majority-vote model is generalized by incorporating inertia into the microscopic dynamics of the spin flipping, where the spin-flip probability of any individual depends not only on the states of its neighbors, but also on its own state.
Abstract: We generalize the original majority-vote model by incorporating inertia into the microscopic dynamics of the spin flipping, where the spin-flip probability of any individual depends not only on the states of its neighbors, but also on its own state. Surprisingly, the order-disorder phase transition is changed from a usual continuous or second-order type to a discontinuous or first-order one when the inertia is above an appropriate level. A central feature of such an explosive transition is a strong hysteresis behavior as noise intensity goes forward and backward. Within the hysteresis region, a disordered phase and two symmetric ordered phases are coexisting and transition rates between these phases are numerically calculated by a rare-event sampling method. A mean-field theory is developed to analytically reveal the property of this phase transition.

40 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023886
20221,975
2021443
2020562
2019609
2018566