Elastic and inelastic collisions of swarms

Armbruster, Dieter; Martin, Stephan; Thatcher, Andrea

doi:10.1016/j.physd.2016.11.008

Cited by 17 publications

(38 citation statements)

References 21 publications

(34 reference statements)

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“…The acting forces are divided into the destination force F dest and the interaction force F int i . The determination of boundary and obstacles forces is done using the function V adapted from swarming models [1,2]. We remark that the equations (2.1) are non-standard in the sense that the first equation onẋ i (t) is not dependent on the velocity v i (t) only.…”

Section: Microscopic Modelmentioning

confidence: 99%

A pedestrian flow model with stochastic velocities: Microscopic and macroscopic approaches

Göttlich¹,

Knapp²,

Schillen³

2018

Kinetic &Amp; Related Models

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We investigate a stochastic model hierarchy for pedestrian flow. Starting from a microscopic social force model, where the pedestrians switch randomly between the two states stop-orgo, we derive an associated macroscopic model of conservation law type. Therefore we use a kinetic mean-field equation and introduce a new problem-oriented closure function. Numerical experiments are presented to compare the above models and to show their similarities.

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Section: Microscopic Modelmentioning

confidence: 99%

A pedestrian flow model with stochastic velocities: Microscopic and macroscopic approaches

Göttlich¹,

Knapp²,

Schillen³

2018

Kinetic &Amp; Related Models

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“…We study the transition from microscopic models of interacting particles to the macroscopic limit describing their motion as coherent ensembles. Such problems naturally arise in the description of biological swarms such as flocks of birds [4,15,19], schools of fish [3], ant [7] or bacterial colonies [26], the movement of pedestrian crowds [22,24] or transport of material [20,32]. In some production facilities, e.g.…”

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confidence: 99%

“…There have been a few studies at the microscopic level to describe the phenomenology of the interaction of flocks with geometrical boundaries. Studies in finite domains of the Vicsek model, see [5] and references therein, and the attractionrepulsion model [4] illustrate how the geometry of the domain influences steady state flocking solutions. In particular, boundaries generate internal excitations in the swarm which causes the flocking solution to break apart.…”

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confidence: 99%

“…In the attraction-repulsion model the relative strength of attraction and repulsion in comparison to the self-propelling forces determine whether flocks scatter elastically or inelastically from a boundary. Similarly when two or more flocks [4] collide they may cross almost without interacting or their formation may be temporarily destroyed and they re-emerge as two flocks with different directions of motions or they may merge into one flock.…”

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confidence: 99%

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Density dependent diffusion models for the interaction of particle ensembles with boundaries

Weißen¹,

Göttlich²,

Armbruster³

2021

KRM

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The transition from a microscopic model for the movement of many particles to a macroscopic continuum model for a density flow is studied. The microscopic model for the free flow is completely deterministic, described by an interaction potential that leads to a coherent motion where all particles move in the same direction with the same speed known as a flock. Interaction of the flock with boundaries, obstacles and other flocks leads to a temporary destruction of the coherent motion that macroscopically can be modeled through density dependent diffusion. The resulting macroscopic model is an advection-diffusion equation for the particle density whose diffusion coefficient is density dependent. Examples describing i) the interaction of material flow on a conveyor belt with an obstacle that redirects or restricts the material flow and ii) the interaction of flocks (of fish or birds) with boundaries and iii) the scattering of two flocks as they bounce off each other are discussed. In each case, the advection-diffusion equation is strictly hyperbolic before and after the interaction while the interaction phase is described by a parabolic equation. A numerical algorithm to solve the advection-diffusion equation through the transition is presented.

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“…Concerning the information flow, it has four classes of basic characteristics describing the spread of flow, the channel for flow, the flow amount in the channel, and the expansion of flow in Sustainability 2019, 11, 710 3 of 32 the system. When the structure has damage, the equilibrium of swarm behavior [19] of the flow may immediately be broken and its characteristics changed at the same time. By analyzing these changing but distinguishable characteristics (such as via AE [20] and local wavenumber technique [21]), it is possible to evaluate whether the structure is damaged or not.…”

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confidence: 99%

Flow Analysis and Damage Assessment for Concrete Box Girder Based on Flow Characteristics

Chang

Kim

et al. 2019

Sustainability

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For a system such as the concrete structure, flow can be the dynamic field to describe the motion, interactions, or both in dynamic or static (Eulerian description) states. Further, various kinds of flow propagate through it from the very start to the end of its lifecycle (Lagrangian description) accompanied by rains, winds, earthquakes, and so forth. Meanwhile, damage may occur inside the structure synchronously, developing from micro-to macro-scale damage, and eventually destroy the structure. This study was conducted to clarify the content of flow which has been implicitly used in the damage detection, and to propose a flow analysis framework based on the combination data space and the theory of dissipative structure theory specifically for nondestructive examination in structural damage detection, which can theoretically standardize the mechanism by which flow characteristics vary, the motion of the structure, or the swarm behavior of substructures in engineering. In this paper, a destructive experiment (static loading experiment) and a following nondestructive experiment (impact hammer experiment) were conducted. According to the experimental data analysis, the changing of flow characteristics shows high sensitivity and efficient precision to distinguish the damage exacerbations in a structure. According to different levels of interaction (intensity) with the structure, the information flow can be divided into two categories: Destructive flow and nondestructive flow. The method used in this research is named as a method of "flow analysis based on flow characteristics", i.e., "FC-based flow analysis".Sustainability 2019, 11, 710 2 of 32 that do not affect or harm the test material, component, or system, such as ultrasonic testing (UT), radiographic testing (RT), infrared thermography (IT), and acoustic emission (AE), among others. In the laboratory experiment, the NDE is often conducted to test the damage after some static loading experiment (one kind of destructive experiments, which would cause damage to the structure). If we view the above methods from a general point, many of the NDE methods share a common concept to show the change of structural status: "dynamic field [5]" or otherwise named as "flow". The dynamic field (flow) is a term defining a field with smooth uninterrupted movement or progress in physics, very commonly used in fluid mechanics nowadays, and also implicitly used in NDE methods; for example, the electromagnetic field in RT and the sound field in AE. Simultaneously, in the static loading experiment, there is a stress field [6] and crack-tip stress field [7] in the static stress-strain response.According to Newton's third law, in the research of damage detection, a global system consists of three parts: The target structure, the environment (referring to everything outside the target structure with a limit domain), and interactions (often described as one kind of flow). In the common sense, an equilibrium state is the state in which the system state variables remain unchanged, as origin...

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Elastic and inelastic collisions of swarms

Cited by 17 publications

References 21 publications

A pedestrian flow model with stochastic velocities: Microscopic and macroscopic approaches

A pedestrian flow model with stochastic velocities: Microscopic and macroscopic approaches

Density dependent diffusion models for the interaction of particle ensembles with boundaries

Flow Analysis and Damage Assessment for Concrete Box Girder Based on Flow Characteristics

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