5 papers · 1 filter
Linear and nonlinear instabilities in highly shear thinning fluid flow through a pipe
Xuerao He, Kengo Deguchi, Runjie Song +1
Shear-thinning fluids flowing through pipes are crucial in many practical applications, yet many unresolved problems remain regarding their turbulent transition. Using highly robus…
Spatial marching with subgrid-scale local exact coherent structures in non-uniformly curved channel flow
Runjie Song, Kengo Deguchi
We propose a novel multiple-scale spatial marching method for flows with slow streamwise variation. The key idea is to couple the boundary region equations, which govern large-scal…
Instability in centrifugally stable shear flows
Kengo Deguchi, Ming Dong
We investigate the linear instability of flows that are stable according to Rayleigh's criterion for rotating fluids. Using Taylor-Couette flow as a primary test case, we develop l…
Three-dimensional coherent structures in a curved pipe flow
Runjie Song, Kengo Deguchi
Dean's approximation for curved pipe flow, valid under loose coiling and high Reynolds numbers, is extended to study three-dimensional travelling waves. Two distinct types of solut…
A sufficient condition for inviscid shear instability: Hurdle theorem and its application to alternating jets
Kengo Deguchi, Makoto Hirota, Timothy Dowling
We propose a simple method to identify unstable parameter regions in general inviscid unidirectional shear flow stability problems. The theory is applicable to a wide range of basi…