期刊
JOURNAL OF FLUID MECHANICS
卷 912, 期 -, 页码 -出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1017/jfm.2020.1100
关键词
pattern formation; bifurcation; Navier-Stokes equations
资金
- Swiss National Science Foundation (SNSF) [200021-160088]
- State Secretariat for Education, Research and Innovation SERI via the Swiss Government Excellence Scholarship
- Swiss National Science Foundation (SNF) [200021_160088] Funding Source: Swiss National Science Foundation (SNF)
The study investigates the impact of symmetry breaking on the three-dimensional plane Couette flow homoclinic snaking, revealing that wall-normal suction can modify the bifurcation structure of solutions. This modification disrupts the connected snakes-and-ladders structure and leads to the creation of previously unknown solution branches.
A specific family of spanwise-localised invariant solutions of plane Couette flow exhibits homoclinic snaking, a process by which spatially localised invariant solutions of a nonlinear partial differential equation smoothly grow additional structure at their fronts while undergoing a sequence of saddle-node bifurcations. Homoclinic snaking is well understood in the context of simpler pattern-forming systems such as the one-dimensional Swift-Hohenberg equation with cubic-quintic nonlinearity. The Swift-Hohenberg solutions closely resemble the snaking solutions of plane Couette flow, yet this remarkable resemblance and the mechanisms supporting homoclinic snaking within the three-dimensional Navier-Stokes equations remain to be fully understood. Studies of Swift-Hohenberg revealed the central importance of discrete symmetries for homoclinic snaking to be supported by an equation. We therefore study the structural stability of the characteristic snakes-and-ladders structure associated with homoclinic snaking in three-dimensional plane Couette flow for flow modifications that break symmetries of the flow. We demonstrate that wall-normal suction modifies the bifurcation structure of three-dimensional plane Couette solutions in the same way a symmetry-breaking quadratic term modifies solutions of the one-dimensional Swift-Hohenberg equation. These modifications are related to the breaking of the discrete rotational symmetry. At large amplitudes of the symmetry-breaking wall-normal suction the connected snakes-and-ladders structure is destroyed. Previously unknown solution branches are created and can be parametrically continued to vanishing suction. This yields new localised solutions of plane Couette flow that exist in a wide range of Reynolds numbers.
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