scholarly journals A forward-looking anticipative viscous high-order continuum model considering two leading vehicles for traffic flow through wireless V2X communication in autonomous and connected vehicle environment

2020 ◽  
Vol 556 ◽  
pp. 124589 ◽  
Author(s):  
Lu Sun ◽  
Ammar Jafaripournimchahi ◽  
Wusheng Hu
Keyword(s):  
Traffic Flow ◽  
Continuum Model ◽  
High Order ◽  
Connected Vehicle ◽  
Flow Through ◽  
Forward Looking

Improved High-Order Model for Freeway Traffic Flow

1998 ◽  
Vol 1644 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Guoqing Liu ◽  
Anastasios S. Lyrintzis ◽  
Panos G. Michalopoulos
Keyword(s):  
Flow Velocity ◽  
Traffic Flow ◽  
Continuum Model ◽  
Hyperbolic Conservation Laws ◽  
Heavy Traffic ◽  
High Order ◽  
Order Model ◽  
Equilibrium Limit ◽  
Characteristic Speed ◽  
Linearized Stability

An improved high-order continuum model is developed based on hyperbolic conservation laws with relaxation, linearized stability analysis, and more realistic considerations of traffic flow. The improved high-order model allows smooth traveling wave solutions as well as contact shocks (different densities moving at the same speed), is able to describe the amplification of small disturbances on heavy traffic, and allows fluctuations of speed around the equilibrium values. Furthermore, unlike existing high-order models, it does not result in negative speeds at the tail of congested regions and disturbance propagation speeds greater than the traffic flow velocity because the improved model has a zero characteristic speed and a nonnegative characteristic speed that is equal to the traffic flow velocity. The relaxation time is a function of density and, in the equilibrium limit, the improved high-order model is consistent with the simple continuum model. The improved high-order model is compared with the simple continuum model. Exemplary test results suggest that the improved high-order model is intuitively correct. Comparison of numerical results with field data suggests that the improved high-order model yields lower error levels than the simple continuum model.

scholarly journals A continuum model for meltwater flow through compacting snow

2017 ◽  
Vol 11 (6) ◽  
pp. 2799-2813 ◽  
Author(s):  
Colin R. Meyer ◽  
Ian J. Hewitt
Keyword(s):  
Continuum Model ◽  
Pore Space ◽  
Water Storage ◽  
Greenland Ice Sheet ◽  
Percolation Process ◽  
Surface Mass ◽  
Run Off ◽  
Flow Through ◽  
Energy Balances ◽  
Mass And Energy Balances

Abstract. Meltwater is produced on the surface of glaciers and ice sheets when the seasonal energy forcing warms the snow to its melting temperature. This meltwater percolates into the snow and subsequently runs off laterally in streams, is stored as liquid water, or refreezes, thus warming the subsurface through the release of latent heat. We present a continuum model for the percolation process that includes heat conduction, meltwater percolation and refreezing, as well as mechanical compaction. The model is forced by surface mass and energy balances, and the percolation process is described using Darcy's law, allowing for both partially and fully saturated pore space. Water is allowed to run off from the surface if the snow is fully saturated. The model outputs include the temperature, density, and water-content profiles and the surface runoff and water storage. We compare the propagation of freezing fronts that occur in the model to observations from the Greenland Ice Sheet. We show that the model applies to both accumulation and ablation areas and allows for a transition between the two as the surface energy forcing varies. The largest average firn temperatures occur at intermediate values of the surface forcing when perennial water storage is predicted.

scholarly journals The Simulation of Sloped Bank Effect Influence on Container Ship Trajectory

2021 ◽  
Vol 9 (11) ◽  
pp. 1283
Author(s):  
Mate Baric ◽  
Robert Mohovic ◽  
Djani Mohovic ◽  
Vinko Pavic
Keyword(s):  
Traffic Flow ◽  
Significant Influence ◽  
Suez Canal ◽  
Container Ship ◽  
Design Standards ◽  
Bank Effect ◽  
Flow Through ◽  
External Forces ◽  
The Impact ◽  
Vessel Speed

The latest container vessel grounding in the Suez Canal, which occurred on 23 March 2021 (the Ever Given), raised many questions regarding the safety of navigation. The sudden concern about safety is due to fears that traffic flow through the Suez Canal could be blocked for longer periods of time. Besides external forces imposed by wind, in this case bank effect had a significant influence on the ship’s grounding. Bank effect occurs due to restricted water flow caused by narrow waterways. Many fairway design standards consider sloped banks such as those of the Suez Canal as unsubstantial in bank-effect forces. This paper analyses the impact of sloped banks on container ship trajectory and proposes minimal distances that may decrease bank-effect forces in order to reduce the risk of vessel grounding and increase the safety of navigation. However, this type of accident has happened before and may occur again due to a small sailing distance from the bank in cases where vessel speed is increased.

Riemann solvers of a conserved high-order traffic flow model with discontinuous fluxes

2022 ◽  
Vol 413 ◽  
pp. 126648
Author(s):  
Dianliang Qiao ◽  
Zhiyang Lin ◽  
Mingmin Guo ◽  
Xiaoxia Yang ◽  
Xiaoyang Li ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Flow Model ◽  
High Order ◽  
Riemann Solvers ◽  
Traffic Flow Model

Continuum Model for Ion Gating in Cochlear Hair Cells

1997 ◽  
Vol 50 (11S) ◽  
pp. S210-S215
Author(s):  
Charles R. Steele
Keyword(s):  
Flow Rate ◽  
Continuum Model ◽  
Mechanical Response ◽  
Elastic Interaction ◽  
Physical Parameters ◽  
Cochlear Hair Cells ◽  
Ion Flow ◽  
Basic Fluid ◽  
Spring Force ◽  
Flow Through

The details of ion flow in cells are important for the macro mechanical response of sensory organs, as in the inner ear of vertebrates. A continuum model for the flow of an ionized fluid through a pore in an elastic wall is considered. With this, the electro-mechanical behavior is readily computed. An interesting result is that two equilibria exist for the flow through a pore with a soft elastic entrance region. At one equilibrium point, the entrance opening is more restricted and the corresponding ion flow rate is much lower. Thus it appears that the tendency of ion channels to pop from an open to a closed state may be a consequence of basic fluid-elastic interaction. With the simple continuum model, various effects can be explored. One is the presence of an external spring force, corresponding to the force of the tip fiber between stereocilia. Another is the effect of an adjacent membrane and pore. The input physical parameters are reasonable and the results for flow rate are consistent with experimental measurements.

scholarly journals Two-pore channels at the intersection of endolysosomal membrane traffic

2015 ◽  
Vol 43 (3) ◽  
pp. 434-441 ◽  
Author(s):  
Jonathan S. Marchant ◽  
Sandip Patel
Keyword(s):  
Nicotinic Acid ◽  
Traffic Flow ◽  
Rab Proteins ◽  
Rab Gtpases ◽  
Ion Permeation ◽  
Voltage Gated ◽  
Proteomic Data ◽  
Flow Through ◽  
Acidic Organelles

Two-pore channels (TPCs) are ancient members of the voltage-gated ion channel superfamily that localize to acidic organelles such as lysosomes. The TPC complex is the proposed target of the Ca2+-mobilizing messenger NAADP, which releases Ca2+ from these acidic Ca2+ stores. Whereas details of TPC activation and native ion permeation remain unclear, a consensus has emerged around their function in regulating endolysosomal trafficking. This role is supported by recent proteomic data showing that TPCs interact with proteins controlling membrane organization and dynamics, including Rab GTPases and components of the fusion apparatus. Regulation of TPCs by PtdIns(3,5)P2 and/or NAADP (nicotinic acid adenine dinucleotide phosphate) together with their functional and physical association with Rab proteins provides a mechanism for coupling phosphoinositide and trafficking protein cues to local ion fluxes. Therefore, TPCs work at the regulatory cross-roads of (patho)physiological cues to co-ordinate and potentially deregulate traffic flow through the endolysosomal network. This review focuses on the native role of TPCs in trafficking and their emerging contributions to endolysosomal trafficking dysfunction.

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