The influence of collision angle for viscous vortex reconnection

2021 ◽  
Vol 33 (9) ◽  
pp. 093608
Author(s):  
J. Hu ◽  
S. D. Peterson
Keyword(s):  
Vortex Reconnection ◽  
Collision Angle

The Analysis and Research of Traffic Accident Velocity Based on C#

2014 ◽  
Vol 505-506 ◽  
pp. 1137-1142
Author(s):  
Li Lin ◽  
Ting Ting Lv
Keyword(s):  
Traffic Accident ◽  
Traffic Accidents ◽  
Front Face ◽  
Vehicle Speed ◽  
Application Range ◽  
Collision Type ◽  
Side Collision ◽  
Speed Identification ◽  
Important Basis ◽  
Collision Angle

In the process of the traffic accidents confirmation, the identification of vehicle speed when accident occurred is often an important basis for accident confirmation. The paper firstly discusses the models of mechanics and solving method for the vehicle front face, rear end, sides face ,slanted side collision based on the theory of collision mechanics ,it describes how to identify the vehicle rate and collision angle based on the model simplification, the theoretical analysis for dealing with the complicated accidents. The common and formulas are studied based on the classical collision mechanics method. The application range, parameters involved in selection and influence of the formulas are analyzed in detail. Finally the program based on C# is developed according to the identified calculation process for vehicle speed of traffic accident. The vehicle speed is obtained by selecting the collision type, entering the relevant accident pattern, inputting the parameters and clicking the command button .The application can store, modify and display results conveniently , improve efficiency on vehicle speed identification effectively and reduce the processing cycle of traffic accident availably.

scholarly journals On Lagrangian and vortex-surface fields for flows with Taylor–Green and Kida–Pelz initial conditions

2010 ◽  
Vol 661 ◽  
pp. 446-481 ◽  
Author(s):  
YUE YANG ◽  
D. I. PULLIN
Keyword(s):  
Incompressible Flows ◽  
Initial Conditions ◽  
Scalar Fields ◽  
Local Geometry ◽  
Optimization Approach ◽  
Vortex Reconnection ◽  
Barotropic Flow ◽  
Lagrangian Surfaces ◽  
Definition Of ◽  
Surface Fields

For a strictly inviscid barotropic flow with conservative body forces, the Helmholtz vorticity theorem shows that material or Lagrangian surfaces which are vortex surfaces at time t = 0 remain so for t > 0. In this study, a systematic methodology is developed for constructing smooth scalar fields φ(x, y, z, t = 0) for Taylor–Green and Kida–Pelz velocity fields, which, at t = 0, satisfy ω·∇φ = 0. We refer to such fields as vortex-surface fields. Then, for some constant C, iso-surfaces φ = C define vortex surfaces. It is shown that, given the vorticity, our definition of a vortex-surface field admits non-uniqueness, and this is presently resolved numerically using an optimization approach. Additionally, relations between vortex-surface fields and the classical Clebsch representation are discussed for flows with zero helicity. Equations describing the evolution of vortex-surface fields are then obtained for both inviscid and viscous incompressible flows. Both uniqueness and the distinction separating the evolution of vortex-surface fields and Lagrangian fields are discussed. By tracking φ as a Lagrangian field in slightly viscous flows, we show that the well-defined evolution of Lagrangian surfaces that are initially vortex surfaces can be a good approximation to vortex surfaces at later times prior to vortex reconnection. In the evolution of such Lagrangian fields, we observe that initially blob-like vortex surfaces are progressively stretched to sheet-like shapes so that neighbouring portions approach each other, with subsequent rolling up of structures near the interface, which reveals more information on dynamics than the iso-surfaces of vorticity magnitude. The non-local geometry in the evolution is quantified by two differential geometry properties. Rolled-up local shapes are found in the Lagrangian structures that were initially vortex surfaces close to the time of vortex reconnection. It is hypothesized that this is related to the formation of the very high vorticity regions.

Plastic Flow of Aluminum in Explosive Welding

2019 ◽  
Author(s):  
V.G. Petushkov ◽  
M.I. Zotov ◽  
L.D. Dobrushin
Keyword(s):  
Plastic Deformation ◽  
Corrosion Resistance ◽  
Plastic Flow ◽  
Explosive Welding ◽  
High Speed ◽  
Contact Point ◽  
Contact Boundary ◽  
High Speed Collision ◽  
Collision Angle

Joining of metals in explosive welding takes place as a result of their plastic deformation during a high speed collision and is usually accompanied by typical formation of waves at the interface. In welding aluminium, the weld boundary can also be straight if the speed of the contact point is νc is ≤ 1900 m/s. These welding conditions make it possible to prevent melting of the metal at the interface and increase at the same time its corrosion resistance. In this article, the effect of the dynamic collision angle on the special features of plastic flow of the metal in the vicinity of the contact boundary in welding sheets of AS5 aluminium is described.

scholarly journals Numerical study of the vortex breakdown and vortex reconnection in the flow path of high-pressure water turbine

2021 ◽  
Vol 2088 (1) ◽  
pp. 012040
Author(s):  
A V Sentyabov ◽  
D V Platonov ◽  
A V Minakov ◽  
A S Lobasov
Keyword(s):  
Vortex Core ◽  
Vortex Breakdown ◽  
Numerical Study ◽  
Pressure Fluctuations ◽  
Hydraulic Turbine ◽  
Sliding Mesh ◽  
Precessing Vortex Core ◽  
Vortex Reconnection ◽  
Water Turbine ◽  
Pressure Water

Abstract The paper presents a study of the instability of the precessing vortex core in the model of the draft tube of a hydraulic turbine. The study was carried out using numerical modeling using various approaches: URANS, RSM, LES. The best agreement with the experimental data was shown by the RSM and LES methods with the modelling of the runner rotation by the sliding mesh method. In the regime under consideration, the precessing vortex rope is subject to instability, which leads to reconnection of its turns and the formation of an isolated vortex ring. Reconnection of the vortex core leads to aperiodic and intense pressure fluctuations recorded on the diffuser wall.

scholarly journals Vortex reconnections in classical and quantum fluids

SeMA Journal ◽  
2021 ◽  
Author(s):  
Alberto Enciso ◽  
Daniel Peralta-Salas
Keyword(s):  
Stokes Equations ◽  
Quantum Fluids ◽  
Navier Stokes ◽  
Pitaevskii Equation ◽  
Global Approximation ◽  
Rigorous Results ◽  
Navier Stokes Equations ◽  
Localization Principle ◽  
Global Smooth Solutions ◽  
Vortex Reconnection

AbstractWe review recent rigorous results on the phenomenon of vortex reconnection in classical and quantum fluids. In the context of the Navier–Stokes equations in $$\mathbb {T}^3$$ T 3 we show the existence of global smooth solutions that exhibit creation and destruction of vortex lines of arbitrarily complicated topologies. Concerning quantum fluids, we prove that for any initial and final configurations of quantum vortices, and any way of transforming one into the other, there is an initial condition whose associated solution to the Gross–Pitaevskii equation realizes this specific vortex reconnection scenario. Key to prove these results is an inverse localization principle for Beltrami fields and a global approximation theorem for the linear Schrödinger equation.

Role of collision angle during dissimilar Al/Cu magnetic pulse welding

2020 ◽  
Vol 25 (7) ◽  
pp. 549-555 ◽  
Author(s):  
Mehdi Pourabbas ◽  
Amir Abdollah-Zadeh ◽  
Morteza Sarvari ◽  
Farid Movassagh-Alanagh ◽  
Majid Pouranvari
Keyword(s):  
Magnetic Pulse ◽  
Magnetic Pulse Welding ◽  
Pulse Welding ◽  
Collision Angle
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