Invariant solutions in a channel flow using a minimal restricted nonlinear model

详细信息    查看全文

• 作者：Fré ; dé ; ric Alizard^a ; ^b ; ^{frederic.alizard@lecnam.net}
• 关键词：Channel flow ; Invariant solutions ; Subcritical transition
• 刊名：Comptes Rendus Mécanique
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：345
• 期：2
• 页码：117-124
• 全文大小：1316 K
• 卷排序：345

文摘

Simulations using a Restricted Nonlinear (RNL) system, where mean flow distortion resulting from Reynolds stress feedback regenerates rolls, is applied in a channel flow under subcritical conditions. This quasi-linear restriction of the dynamics is used to study invariant solutions located in the bulk of the flow found recently by Rawat et al. (2016) [14]. It is shown that the RNL system truncated to a single streamwise mode for the perturbation supports invariant solutions that are found to bifurcate from a relative periodic orbit into a travelling wave solution when the spanwise size is increasing. In particular, the travelling wave solution exhibits a spanwise localized structure that remains unchanged for large values of the spanwise extent as the invariant solution lying on the lower branch found by Rawat et al. (2016) [14]. In addition, travelling wave solutions provided by this minimal RNL system are self-similar with respect to the Reynolds number based on the centreline velocity, and the half-channel height varying from 2000 to 5000.