The vortex shedding and wake development of a two-dimensional viscous incompressible flow generated by circular cylinder which begins its rotation translation impulsively in stationary fluid is investigated hybrid scheme at Reynolds number 1000. rotational to translational speed ratio α varies from 0 6. method used calculate the can be considered as combination diffusion-vortex vortex-in-cell method. More specifically, full field divided into two regions: near body surface solve...

We numerically study a vortex ring impacting flat wall with an angle of incidence θ ≥ 0°) in three dimensions by using the lattice Boltzmann equation. The hydrodynamic behaviour ring–wall interacting flow is investigated systematically varying range 0° ≤ 40° and Reynolds number 100 Re 1000, where based on translational speed initial diameter ring. quantify effects evolution structure other fields two dimensions. observe distinctive regions θ– parameter space. First, low-Reynolds-number...

The evolution of a viscous elliptic vortex ring in an initially quiescent fluid or linear shear flow is numerically simulated using lattice Boltzmann method. A wide range parameters are considered, namely, aspect ratios (AR) (1 ≤ AR 8), core radius to (σ0) (0.1 σ0 0.3), Reynolds number (Re) (500 Re 3000), and rate (K) (0 K 0.12). study aims fill the gap current knowledge dynamics also address issue whether undergoes stretching compression during axis-switching. In fluid, results show that...

The pseudopotential lattice Boltzmann method (LBM) becomes popular in simulating the boiling heat transfer problems. By using interaction force determined from an equation of state, phenomenon can occur spontaneously according to thermodynamics, which avoids empirical models for boiling. However, this model also brings additional cause instability, severe at high density ratios. Therefore, most its previous simulations are conducted saturated temperatures with low Since instability usually...

We simulate a two-dimensional incompressible flow around rotating circular cylinder near plane wall at the Reynolds number Re=200 by using lattice Boltzmann equation with multiple relaxation times. investigate pattern in parameter space of rotational rate γ≔ωa∕U and normalized gap h≔H∕D, where ω is angular velocity cylinder, D are radius diameter, respectively, U inflow velocity, H between wall. quantify effects γ h on hydrodynamic forces frequency vortex shedding from cylinder. Our results...

A recent theoretical study [Borisov, Kilin, and Mamaev, “The dynamics of vortex rings: Leapfrogging, choreographies the stability problem,” Regular Chaotic Dyn. 18, 33 (2013); Borisov et al., Leapfrogging in an ideal viscous fluid,” Fluid Res. 46, 031415 (2014)] shows that when three coaxial rings travel same direction incompressible fluid, each alternately slips through (or leapfrogs) other two ahead. Here, we use a lattice Boltzmann method to simulate with identical initial circulation,...

In this paper, we numerically simulate a vortex ring impacting permeable wall by using lattice Boltzmann method. The study is motivated recent publications on ring/permeable interaction and our desire to address some of the unanswered questions such as evolution core vorticity, kinetic energy, enstrophy flow field during interaction. simulation was conducted for wide range parameters, namely, open-area ratios (ϕ) (0 ≤ ϕ 1), wire structure dimensions (A) (0.015 A 0.1), wall-thicknesses (H) H...

In this paper, we use a lattice Boltzmann method to study the effect of swirl on dynamics an isolated three-dimensional vortex ring in viscous incompressible fluid. We focus fixed Reynolds number 800 and vary magnitude core size. Results show that increasing for size or causes slow down even travel backward initially. A simplified physical explanation dynamic behavior is proposed. Our results further while weak filaments undergo helical winding, sufficiently strong transforms these windings...

Abstract A novel finite point method is developed to simulate flow problems. The mashes in the traditional numerical methods are supplanted by distribution of points calculation domain. local interpolation based on properties Taylor series expansion used construct an approximation for unknown functions and their derivatives. An upwind‐dominated scheme proposed efficiently handle non‐linear convection. Comparison with difference solutions two‐dimensional driven cavity experimental results...

A linear shear incompressible flow over a square cylinder at Reynolds number of 100 is investigated using the lattice Boltzmann method. The rate K ranges from 0 to 0.5. influence on frequency vortex shedding cylinder, lift, and drag forces exerted determined together with patterns around cylinder. computational results not only confirm suppression effect but also reveal some basic features evolution K.

The motion and deformation of a vortex ring in linear or simple shear flow have been simulated numerically by using the lattice Boltzmann method with multiple relaxation times. study is motivated recent experiment [T. T. Lim, K. B. Lua, Thet, Phys. Fluids 20, 051701 (2008)], which shows that propagating uniform cross does not experience Kutta lift undergo tilting deformation. focus present to examine effect on ring. Numerical approach adopted here because truly difficult generate...

Past experimental and numerical studies show that when two identical circular vortex rings of moderate Reynolds number collide head-on, ringlets are generated around the circumference primary propagated radially outward through self-induction. Here, we dissimilarity in core sizes between colliding rings, despite having same circulation, can significantly affect outcome collision. This finding may help to explain asymmetry formation observed some studies, which could be due imperfections ring...

It is well known that head-on collision of two identical circular vortex rings at moderate Reynolds numbers generates secondary ringlets propagate radially away from the center primary rings. In this paper, we show through numerical simulations deforming ring shape a circle to an ellipse can lead drastic changes in flow topology during collision. The computations are performed for range parameters, including aspect ratio elliptic rings, core size (η), and azimuthal angle between their major...

In this paper, lattice Boltzmann method was undertaken to study the dynamics of a vortex ring bubble (or ring) in viscous incompressible fluid. The is motivated partly by our desire assess whether keeps increasing its radius and decreasing rise velocity as it rises through fluid predicted Turner [“Buoyant rings,” Proc. R. Soc. London, Ser. A 239, 61 (1957)]10.1098/rspa.1957.0022 Pedley [“The toroidal bubble,” J. Fluid Mech. 32, 97 (1968)]10.1017/S0022112068000601, or does like rising bubble,...