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We consider a numerical approach for a covariant generalised Navier-Stokes equation on general surfaces and study the influence of varying Gaussian curvature on anomalous vortex-network active turbulence. This regime is characterised by…

Fluid Dynamics · Physics 2021-08-03 M. Rank , A. Voigt

We investigate the turbulent dynamics of a two-dimensional active nematic liquid crystal con- strained on a curved surface. Using a combination of hydrodynamic and particle-based simulations, we demonstrate that the fundamental structural…

Soft Condensed Matter · Physics 2019-05-01 D. J. G. Pearce , Perry W. Ellis , Alberto Fernandez-Nieves , L. Giomi

Recent experiments demonstrate the importance of substrate curvature for actively forced fluid dynamics. Yet, the covariant formulation and analysis of continuum models for non-equilibrium flows on curved surfaces still poses theoretical…

We consider surface finite elements and a semi-implicit time stepping scheme to simulate fluid deformable surfaces. Such surfaces are modeled by incompressible surface Navier-Stokes equations with bending forces. Here, we consider closed…

Numerical Analysis · Mathematics 2023-05-03 Veit Krause , Axel Voigt

The existence and dynamical role of particular unstable Navier-Stokes solutions (exact coherent structures) is revealed in laboratory studies of weak turbulence in a thin, electromagnetically-driven fluid layer. We find that the dynamics…

Chaotic Dynamics · Physics 2018-08-01 Balachandra Suri , Jeffrey Tithof , Roman O. Grigoriev , Michael F. Schatz

This review introduces the elasticity theory of two-dimensional crystals and nematic liquid crystals on curved surfaces, the energetics of topological defects (disclinations, dislocations and pleats) in these ordered phases, and the…

Soft Condensed Matter · Physics 2014-01-21 Vinzenz Koning , Vincenzo Vitelli

In fairly general conditions we give explicit (smooth) solutions for the potential flow. We show that, rigorously speaking, the equations of the fluid mechanics have not rotational solutions. However, within the usual approximations of an…

Fluid Dynamics · Physics 2023-09-21 Marian Apostol

In the present work, we investigate a numerical one-dimensional solver to the Navier-Stokes equation that retains all terms, including both pressure and dissipation. Solutions to simple examples that illustrate the actions of the nonlinear…

Fluid Dynamics · Physics 2023-03-30 Preben Buchhave , Clara Marika Velte

Governing equations of motion for a viscous incompressible material surface are derived from the balance laws of continuum mechanics. The surface is treated as a time-dependent smooth orientable manifold of codimension one in an ambient…

Mathematical Physics · Physics 2018-10-10 Thomas Jankuhn , Maxim A. Olshanskii , Arnold Reusken

Incompressible fluids on curved surfaces are considered with respect to the interplay between topology, geometry and fluid properties using a surface vorticity-stream function formulation, which is solved using parametric finite elements.…

Fluid Dynamics · Physics 2014-06-20 Sebastian Reuther , Axel Voigt

This paper presents a topology optimization approach for surface flows, which can represent the viscous and incompressible fluidic motions at the solid/liquid and liquid/vapor interfaces. The fluidic motions on such material interfaces can…

Computational Physics · Physics 2020-05-18 Yongbo Deng , Weihong Zhang , Jihong Zhu , Junqiang Bai , Zhenyu Liu , Jan G. Korvink

By analogy with the kinetic theory of gases, most turbulence modeling strate- gies rely on an eddy viscosity to model the unresolved turbulent fluctuations. How- ever, the ratio of unresolved to resolved scales - very much like a degree of…

Fluid Dynamics · Physics 2016-08-24 Marcello Righi

Liquid crystals with molecules constrained to the tangent bundle of a curved surface show interesting phenomena resulting from the tight coupling of the elastic and bulk free energies of the liquid crystal with geometric properties of the…

Soft Condensed Matter · Physics 2021-03-17 Ingo Nitschke , Sebastian Reuther , Axel Voigt

The problem of low Reynolds number turbulence in active nematic fluids is theoretically addressed. Using numerical simulations I demonstrate that an incompressible turbulent flow, in two-dimensional active nematics, consists of an ensemble…

Soft Condensed Matter · Physics 2015-08-04 Luca Giomi

We consider the derivation and numerical solution of the flow of passive and active polar liquid crystals, whose molecular orientation is subjected to a tangential anchoring on an evolving curved surface. The underlying passive model is a…

Computational Physics · Physics 2019-01-18 Ingo Nitschke , Sebastian Reuther , Axel Voigt

In this paper, we continue the discussion as done in \cite{CTZ15} on turbulent channel flow described by the Navier-Stokes model and the Navier-Stokes-alpha model. We study the non-stationary solutions for the Navier-Stokes equations and…

Analysis of PDEs · Mathematics 2018-10-24 J. Tian , B. Zhang

A stochastic version of a modified Navier-Stokes equation (introduced by Prouse) is considered in a 3-dimensional torus. We prove existence and uniqueness of martingale solutions. A different model with the non linearity given by a power 5…

Probability · Mathematics 2009-09-29 B. Ferrario , F. Flandoli

We study steady vortex sheet solutions of the Navier-Stokes in the limit of vanishing viscosity at fixed energy flow. We refer to this as the turbulent limit. These steady flows correspond to a minimum of the Euler Hamiltonian as a…

Fluid Dynamics · Physics 2021-03-31 Alexander Migdal

Many researches show that the complicated motion of fluid, such as turbulence, cannot be well solved by the Navier-Stokes equation. Chen Zida has founded that the definition of vortex, based on the Stokes decomposition, cannot well describe…

Fluid Dynamics · Physics 2007-05-23 Jianhua Xiao

We introduce several new models whose common feature is to take into account effects from topological vorticity. The macroscopic unknown is driven by a dissipative anomalous diffusion (of SQG-type) and is coupled with the orientation of the…

Analysis of PDEs · Mathematics 2026-01-27 Fanghua Lin , Yannick Sire , Yantao Wu , Yifu Zhou
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