Inertia

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

An investigation of laminar radial flow between two parallel discs

Abstract: Experiments have been carried out to test recent theoretical predictions of the pressure distribution for laminar flow between parallel discs, including inertia effects. The experimental investigation covered the condition where the inertia effects were always completely dominant over the central region of the discs in contrast to other recent experimental work on the problem where the central injection diameter was considerably larger. The present experiments subject the theories to a stringent test, due to the dominance of the inertia effects, and it is found that the inertia effects predicted by the various theoretical analyses are significantly smaller than those shown by the experimental results. It is suggested that the theoretical approach requires further development before it will cover the conditions where the central injection diameter is small.

Impact of synthetic inertia from wind power on the protection/control schemes of future power systems: Simulation study

Abstract: Future power systems face several challenges; one of them is the use of high power converters that decouple new energy sources from the AC power grid. This decreases the total system inertia affecting its ability to overcome system frequency's disturbances. The wind power industry has created a controller to enable inertial response on wind turbines generators: Artificial, Emulated, Simulated, or Synthetic Inertial. This paper deals with issues related to the synthetic inertia of wind turbines based on full-converters and their effect on the frequency protection/control schemes during the recovery period after system frequency disturbances happen. The main contribution of this paper is to demonstrate (based on simulations) the recovery period of under-frequency transients on future power systems which integrate wind turbines with synthetic inertia capability not completely avoid worse scenarios in terms of under-frequency load shedding. The extra power delivered from a wind turbine during frequency disturbances can substantially reduce the rate of change of frequency providing time for the active governors to respond. However, synthetic inertia might not completely avoid under-frequency load shedding. (6 pages)

Multi-Flexible Body Dynamics Capturing Motion-Induced Stiffness

Abstract: This paper presents a multi-flexible-body dynamics formulation incorporating a recently developed theory for capturing motion-induced stiffness for an arbitrary structure undergoing large rotation and translation accompanied by small vibrations. In essence, the method consists of correcting dynamical equations for an arbitrary flexible body, unavoidably linearized prematurely in modal coordinates, with generalized active forces due to geometric stiffness corresponding to a system of 12 inertia forces and 9 inertia couples distributed over the body. Computation of geometric stiffness in this way does not require any iterative update. Equations of motion are derived by means of Kane’s method. A treatment is given for handling prescribed motions and calculating interaction forces. Results of simulations of motions of three flexible spacecraft, involving stiffening during spinup motion, dynamic buckling, and a slewing maneuver, demonstrate the validity and generality of the theory.

Analysis and Improvement of Particle Swarm Optimization Algorithm

Abstract: The effects of inertia weight on particle swarm optimization (PSO) performance are analyzed. A novel method of selecting inertia weight in PSO is developed, which can tune the expectations of inertia weights adaptively when the inertia weights are randomly selected and lead to effectively balance between the local and global search ability. Results of the two benchmark functions indicate that the PSO algorithm based on the strategy of random inertia weight (RIW) has been significantly improved on both optimization speed and computational accuracy.