Top PDF Inertial effects in suspension dynamics

Inertial effects in suspension dynamics

Inertial effects in suspension dynamics

This work analyses the role of small but finite particle inertia on the microstructure of sus- pensions of heavy particles subjected to an external flow. The magnitude of particle inertia is characterized by the Stokes number (St), defined as the ratio of the inertial relaxation time of a particle to the flow time scale. Fluid inertia is neglected so that the fluid motion satisfies the quasi-steady Stokes equations. The statistics of the particles is governed by a Fokker- Planck equation in position and velocity space. For small St, a multiple scales formalism is developed to solve for the phase-space probability density of a single spherical Brownian par- ticle in a linear flow. Though valid for an arbitrary flow field, the method fails for a spatially varying mass and drag coefficient. In all cases, however, a Chapman-Enskog-like formulation provides a valid multi-scale description of the dynamics both for a single Brownian particle and a suspension of interacting particles. For long times, the leading order solution simplifies to the product of a local Maxwellian in velocity space and a spatial density satisfying the Smoluchowski equation. The higher order corrections capture both short-time momentum relaxations and long-time deviations from the Maxwellian. The inertially corrected Smolu- chowski equation includes a non-Fickian term at O(St).
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Development Of Multibody Dynamics (MBD) Method For UTeM FV Malaysia Racing Car Suspension System

Development Of Multibody Dynamics (MBD) Method For UTeM FV Malaysia Racing Car Suspension System

Reference point directions indicate component position and introduction by inserting a nearby facilitate framework in that component, determining the X-Y position of the neighborhood coordinate root, and introduction edge between a nearby pivot and the worldwide inertial hub. Regularly neighborhood tomahawks are meant with a prime, for instance x′ or y'. Requirement mathematical statements are composed in light of the kind of movement every joint permits between nearby components. For instance, a revolute joint would oblige both X and Y interpretation. Since the position and introduction of every component is straightforwardly indicated, little pre-and post-preparing are important to decide every joint's supreme movement. The principle drawback of this framework is that the vast number of directions it requires can extend reenactment time.
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Car Dynamics Using Quarter Model And Passive Suspension, Part Iv: Destructive Miniature Humps (Bumps)

Car Dynamics Using Quarter Model And Passive Suspension, Part Iv: Destructive Miniature Humps (Bumps)

This work presents three types of miniature humps or bumps. This covers polynomial, circular and trapezoidal bumps. The dynamics of a quarter-car model are investigated when crossing those humps to assess the destructive effect of such bumps to reach the conditions of ride comfort of drivers and passengers. The study assumed passive car suspension elements of linear characteristics. It covers car crossing speed between 0.25 and 10 km/h, and bump dimensions of 305 mm length and 57 mm height. A ride comfort diagram is presented using MATLAB simulation using the quarter-car model allowing the design of the simple harmonic hump for any desired hump-crossing speed in the range 0.25 to 10 km/h. The polynomial bump was superior for crossing speeds up to 0.65 km/h. Destructive effects are expected if speeds exceed 1.85 to 2.40 km/h depending on the bump type.
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Population dynamics of two suspension-feeding bivalves on a sheltered beach in southeastern Brazil

Population dynamics of two suspension-feeding bivalves on a sheltered beach in southeastern Brazil

(Hiroki 1977). This species is exploited by commercial and recreational harvesters on the Brazilian coast because of its high abundance and protein value (Arruda-Soares et al. 1982). Previous studies have addressed its demography and growth (Monti et al. 1991); embryonic, larval and post- larval development (Moue¨za et al. 1999); functional mor- phology (Narchi 1972); osmotic regulation (Leonel et al. 1983); and depuration effects on trace metals (Wallner- Kersanach et al. 1994). Already Diplodonta punctata has a distribution from North Carolina to Chile, where it is found in sandy and muddy bottoms (Rios 1994). There is only a study about biological aspects of D. punctata (Domaneschi 1979).
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Incorporating kinetic effects on Nernst advection in inertial fusion simulations

Incorporating kinetic effects on Nernst advection in inertial fusion simulations

figure 3 and the bottom panel of figure 9 in [79]), this employed the newly implemented MHD suite (including Nernst) outlined in [ 8 ] . These lineouts were located 3 mm from the centre of the capsule, starting in the low-density gas- fill at r = 0 and ending just inside the partially heated hohl- raum wall at r = 2.76 mm, and used to initialise a 100 ps VFP relaxation simulation using 1D planar geometry. Again, only temperature and magnetic profiles were allowed to evolve while the density profile was fixed by neglecting ion hydro- dynamics and using the zero current constraint. In order to maintain consistency with the rest of this paper and to rein- force the fact that planar geometry was used we will from this point on use the Cartesian coordinates x, y, z in place of their cylindrical counterparts r, z, ( − )f. The initial and final ionisation, electron density, temperature and magnetic field profiles are illustrated in figure 10.
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Inertial effects in three-dimensional spinodal decomposition of a symmetric binary fluid mixture : a lattice Boltzmann study

Inertial effects in three-dimensional spinodal decomposition of a symmetric binary fluid mixture : a lattice Boltzmann study

The LB method is not generally stable. In fact, our experience suggests that, whatever parameters are chosen, any run would eventually become unstable if continued for long enough; this is not dissimilar to some molecular dynamics algorithms, Allen & Tildesley (1987). During testing, a reliable picture was acquired of the characteristic way in which this happens. When the inaccuracies have built up to the point of failure, the velocities become very large over a small number of time steps until numerical overflow causes the code to stop running. There seems to be no danger of taking data from a period when the system might be far from accurate but still apparently running successfully, since the onset is so rapid. Thus there are several runs among the set used for final data analysis where the run ended prematurely due to instabilities, but the data prior to the instability has been considered sufficiently reliable to be used.
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The Relevance of the Marshallian Concept of Normality in Interior and in Inertial Dynamics as Revisited by G. SHACKLE and J. KORNAI

The Relevance of the Marshallian Concept of Normality in Interior and in Inertial Dynamics as Revisited by G. SHACKLE and J. KORNAI

Normal does not mean competitive, at least not in the modern sense of perfect competition. According to Marshall, market and normal prices alike are brought about by a "multitude of influences of which some rest on a moral basis and some on physical; of which some are competitive and some are not. It is to the persistence of the influences considered, and the time allowed for them to work out their effects that we refer when contrasting market and normal price, and again when contrasting the narrower and the broader use of the term normal price" (Marshall, [1890] 1961, p. 348). Meanwhile, although the normal price is determined by factors which are not solely competitive, for Marshall, the normal usually implies a good deal of competition iii . In fact, the normal price is based on some kind of "expectation", conventions and the attitudes of producers and consumers. The "normal" has many dimensions, not only those related to competitive market forces but also those which lie outside the market and determine the structure of the market. Borrowing the military distinction between tactics and strategy, Marshall contends that in economics ‘tactics’ refer to those outward forms and accidents of economic organisation which depend on temporary or local aptitudes, customs and relations of classes, on the influence of individuals, or on the changing factors and needs of production. Hence market value belongs to tactics. ‘Strategy’, in contast, corresponds to the more "fundamental substance of economic organisation", which depends mainly on such wants and activities, such preferences and aversions as are "found in man everywhere". Indeed, the human needs and preferences are not always the same in form, or even in substance; yet they have "a sufficient element of permanence and universality
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Effects of Flexibility and Suspension Configuration of Main Shaft on Dynamic Characteristics of Wind Turbine Drivetrain

Effects of Flexibility and Suspension Configuration of Main Shaft on Dynamic Characteristics of Wind Turbine Drivetrain

Using the lumped parameter method, many dynamic models of gearbox, including planetary gear stage and parallel gear stage, are proposed, but only two transla- tional, one rotational and one axial degrees of freedom (DOFs) for each component are considered in these models. Shi et al. [14] built a torsional dynamic model of gearbox to investigate the system responses. Zhao et al. [15] investigated the dynamic characteristics of gearbox considering the variable input torque. Srikanth et al. [16] investigated the effects of stochastic aerodynamic load on the dynamic behaviors of wind turbine drivetrain. Wei et  al. [17] established a multi-stage gear transmission system to investigate the effects of uncertain parameter due to uncertainties in geometric and material properties of wind turbine gearbox. Zhu et al. [18, 19] built a cou- pled nonlinear dynamic model to investigate the dynamic responses of wind turbine gearbox considering the flex- ible pin. Zhai et al. [20] studied the dynamic mesh forces in the wind turbine gearbox considering the assembly errors of carrier. However, the previous studies [14–20] on the gearbox dynamics are very limited and mainly focus on the dynamic characteristics of gearbox ignor- ing the coupled effects of main shaft. Little attention is
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Ocean Circulation Dynamics and Transport Connectivity in the Intra-Americas Sea on Inter-annual, Seasonal, Synoptic and Inertial Time Scales.

Ocean Circulation Dynamics and Transport Connectivity in the Intra-Americas Sea on Inter-annual, Seasonal, Synoptic and Inertial Time Scales.

Some other studies in the GOM also reveal the effects of physical environment on modulating the transport of biological species. The tidal oscillations along the west Florida coast and the upwelling-downwelling cycles developed in response to the passage of cold fronts could cause the local retention of bay scallop larvae along west Florida (Arnold et al., 1998). The recirculation and gyre circulation formed in the Tortugas area potentially enhanced larval retention and recruitment into the Florida Keys (Lee and Williams, 1999).Red Snapper (scientific name) larval transport in the Northern GOM was found to be dependent on the wind stress and the coastal flow (Johnson et al., 2009). Information on potential larval dispersal and population connectivity over the entire IAS is limited. Although limited previous work showed the many reef fish species are limited due to larval movement(Cowen et al., 2006), the background flow taken into account in the study indeed needs to include of flow variability at time scales from seasonal to interannual.
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Heavy vehicle pitch dynamics and suspension tuning

Heavy vehicle pitch dynamics and suspension tuning

Studies on coupled bounce and pitch motions of automobiles have resulted in some guidelines on suspension design in order to achieve pitch ride control. A few studies have investigated the effects of suspension tuning for passenger cars on ride performance enhancement. The simulation results obtained for a 4-DOF pitch plane model suggested that the front/rear suspension stiffness ratio significantly affects pitch displacement responses (Crolla and King, 1999), while the well-known ‘Olley’s tuning’ is beneficial at higher speeds (Sharp and Pilbeam, 1993; Sharp, 2002). Odhams and Cebon (2006) developed a pitch plane vehicle model with coupling between the front and rear suspensions, where the conventional unconnected suspension was shown to be a special case of coupled suspension. The study presented that pitch plane formulations leaded to a relation between the bump and pitch response of an automobile, which was similar to the concept of Static Margin used in vehicle handling analysis. The study concluded that for the unconnected suspensions, the ‘Olley’s tuning’ provided a nearly optimal solution for minimizing horizontal acceleration at the chest. The resulting vertical chest acceleration, however, could not be considered optimal. The study also demonstrated that an interconnected suspension with lower pitch stiffness, opposed to the conventional unconnected suspension, could offer benefits for improving dynamic tire force and body acceleration responses of a passenger car.
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Effect of shape on inertial particle dynamics in a channel flow

Effect of shape on inertial particle dynamics in a channel flow

Figure 1, both sampled at locations of x + = 11.6 and 300. A semi-logarithmic scale is used for the PDFs to emphasise the shape of the tails. It is seen that the PDF of the particle wall-normal velocity in the buffer region is less symmetric with respect to 0 than the PDF of the particles at the channel centreError! Reference source not found.. Also, although there is some similarity between the frequency of the particle velocity for the two non-spherical particles, differences are apparent between these particles and their spherical counterparts. These differences are seen at both sample locations, although they are less significant at the channel centre. The peak in the PDF of the normalised wall-normal velocity is also clearly higher for the spherical particles at both locations, implying an increased probability of finding spherical particles with a zero wall-normal velocity. These results imply that it is likely, with further simulation time, that particle preferential concentration at the walls of the channel will vary depending on the particular particle shape, although further work is required to quantify such effects. For the normalised wall-normal acceleration results of Fig. 8, differences between the different particle types are less apparent than for the wall-normal particle velocity. The tail of the PDFs is therefore similar for all the particles, although differences do occur between the various shapes, especially at the peak values where ( a w  a w ) / a w,rms  0 .
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Fusion of Force-Torque Sensors, Inertial Measurements Units and Proprioception for a Humanoid Kinematics-Dynamics Observation

Fusion of Force-Torque Sensors, Inertial Measurements Units and Proprioception for a Humanoid Kinematics-Dynamics Observation

In the presence of a force and torque applied on the foot the compliant part is subject to deformation. We can model the flexibility force response to deformation as a rotational and translational spring-damper. By doing so, we link torque/forces to kinematic deviation. On the other hand contact forces drive the floating-base kinematics and gravitational effects on the robot. Reciprocally, we have to take into account that a humanoid robot is not a rigid body. Actuated gesticulation lead to variations of angular momenta and center of mass position, which modifies contact forces and torques and therefore influences partially the flexibility deformation. If we consider all these relations between contact forces, weight, gesticulation, and flexibility deformation we obtain a dynamical system that may predict robot kinetics and even balance.
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SOLUTION APPROACHES TO DIFFERENTIAL EQUATIONS OF MECHANICAL SYSTEM DYNAMICS: A CASE STUDY OF CAR SUSPENSION SYSTEM

SOLUTION APPROACHES TO DIFFERENTIAL EQUATIONS OF MECHANICAL SYSTEM DYNAMICS: A CASE STUDY OF CAR SUSPENSION SYSTEM

time. This means the passengers sitting in the auto- mobile will feel some amount (approx. 30% of the total time taken for this simulation) of vibration at the starting of the car, it goes decreasing gradually and becomes stable. In order to eliminate or reduce vibration at the settling time a feedback controller can be added into the system to improve the perfor- mance of the suspension. This allows the suspen- sion system exhibit good comfort by dissipating the vibration energy through the damper.

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A study on some basic features of inertial oscillations and near-inertial internal waves

A study on some basic features of inertial oscillations and near-inertial internal waves

In the vertical direction, currents display a two-layer struc- ture, with their phase being opposite between the surface and lower layers. They are maximum at the surface, and have a weaker maximum in the lower layer ( ∼ 40 m), with a minimum at a depth of ∼ 20 m. The velocity gradually di- minishes to zero at the bottom due to the bottom friction. This is the typical vertical structure of shelf sea inertial os- cillations, which have been frequently observed (Shearman, 2005; MacKinnon and Gregg, 2005). In practice, this verti- cal distribution can be modified due to the presence of other processes, such as the surface maximum being pushed down to the subsurface (e.g. Chen et al., 2015a). Note that without stratification in this simulation the near-inertial internal wave is absent. However, this two-layer structure of inertial oscil- lations looks ‘baroclinic’, which makes it easy to be mistak- enly attributed to the near-inertial internal wave (Pettigrew, 1981).
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Extracting Dynamics Matrix of Alignment Process for a Gimbaled Inertial Navigation System Using Heuristic Dynamic Programming Method

Extracting Dynamics Matrix of Alignment Process for a Gimbaled Inertial Navigation System Using Heuristic Dynamic Programming Method

In the present studybased onthe idea of HDP, we extract a new internal dynamics matrix identification method. At first, we introduce the discrete time HJB, then, we useheuristic dynamic programming algorithm for solving HJB online, and finally introduce two neural network parametric structures to approximate the optimal cost function and policy. At last, using the main results obtained, we extract an estimator for the internal dynamics estimation of a discrete linear system.

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Housing Price Dynamics and Their Effects

Housing Price Dynamics and Their Effects

When we compare across cohorts, the differences are very large for some attributes, i.e. the 2002-2003 cohort has less adjustable rate mortgages than 2003-2004 cohort, 2004- 2005 cohort and 2005-2006 cohort. These types of differences can be explicitly captured by the use of purchase year fixed effects. Although there are some notable differences across cohorts, the differences across terciles are either small or follow the same pattern across cohorts for all three terciles when not small, and so are captured by tract FEs. For example, when we move from the 1st tercile to the 3rd one, the fraction of transactions with original loan to value ratios higher than 0.95 increases first and then declines, both in the whole sample and in the four cohorts with different purchase years. These results suggest that this model does not contain strong interaction between changes in mortgage composition across time and the equity loss across tracts that are used to identify the model.
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Numerical study on inertial effects on liquid vapor flow using lattice Boltzmann method

Numerical study on inertial effects on liquid vapor flow using lattice Boltzmann method

Porous media containing liquid and vapor ubiquitously exist in a large variety of natural resources and modern applications in energy engineering [1,2]. An elaboration of these complex multiphase flows at the pore scale calls for accurate resolutions of the underlying porous solid skeletons, which are practically unavailable in many scenarios. Alternatively, a simple mathematical description averaged over the so-called representative elementary volume (REV) was developed to capture effective gross flow characteristics without the underlying pore-scale details [3]. One of the most representative REV-scale models is Darcy equation [4]. However, this equation is found insufficiently accurate in intermediate and high flow-rate problems, e.g., oil and gas recovery in open fractures [5] where the inertial force plays an important role. Therefore, this work will focus on liquid-vapor flow in porous media with co-existence of the Darcy, inertial and capillary forces. We aim at developing a robust and efficient lattice Boltzmann (LB) model to investigate the interplay among these forces and revealing the inertial effects at the REV scale on two-phase flow and mass transfer in porous media where the flow rate is large.
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Computer algebra models the inertial dynamics of a thin film flow of power law fluids and other non-Newtonian fluids

Computer algebra models the inertial dynamics of a thin film flow of power law fluids and other non-Newtonian fluids

∂y = (1 − γ)u on y = 1 , (3) where E is an Euler parameter that we are free to vary to improve con- vergence: when γ = 1 this boundary condition reduces to the original (2) and corresponds to the dynamics of interest; but when γ = 0 the boundary conditions and pde have the neutral mode u = e y of any constant ‘shear’ e . The marvellous aspect of the boundary condition (3) is that when γ = 0 the ‘shear’ solutions u = e y forms a space of exact equilibria of the nonlin- ear problem. We construct a centre manifold model of the dynamics about the space of equilibria that exists when γ = 0 . Consequently, the centre manifold model is global in the order parameter e .
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An inertial S-iteration process

An inertial S-iteration process

In this paper, we establish a new iteration method, called an InerSP (an inertial S-iteration process), by combining a modified S-iteration process with the inertial extrapolation. This strategy is for speeding up the convergence of the algorithm. We then prove the convergence theorems of a sequence generated by our new method for finding a common fixed point of nonexpansive mappings in a Banach space. We also present numerical examples to illustrate that the acceleration of our algorithm is effective.

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Dynamics of freight cars on bogies model 18-1711 with different wedge de-signs of spring suspension

Dynamics of freight cars on bogies model 18-1711 with different wedge de-signs of spring suspension

Purpose. To analyze the results of the study of dynamic parameters of a gondola car, model 12-1704-04 with axle load 23.5 ton in bogies, models 18-1750 and two gondola cars, model 12-1905 with axial load of 25 ton, one of which is equipped with bogies, model 18-1711 with friction wedges of spring suspension with spatial form with increased angle to the horizontal line of intersection of the contact surfaces between the wedge and bolster. The other gondola car, model 12-1905 is equipped with bogies of the same model on which the friction wedges fitted with a flat form of contact surface. It has an angle of inclination like a wedge of bogie, model 18-100. On the basis of the obtained results to draw conclusions about the feasibility of unification design bogie bolster, model 18-1711 with bogie, model 18-100 by contact surfaces with elements of spring suspension. Methodology. Research on dynamic performance of cars was performed during running dynamic tests of specimens of freight cars in experimental train consisting of two locomo- tives, a laboratory, and three gondola cars of the above mentioned models. Findings. Main results of dynamic studies are presented as graphs of indicators on the speed of the train and the experimental evidence that the freight gondola cars on bogies, model 18-1711 with flat-shaped wedges, in most cases are better than the others. Originality. Research results of cars on bogies, model 18-1711 were obtained. They let assess the dependence of the dynamic performance of the car from the design of the friction wedges of spring suspension. Practical value. Cast parts of bogie, model 18-1711 with 25 ton axle load can be used as a replacement of defective parts of bogie, model 18-100 and its analogs.
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