6 papers
Discontinuous transition to shear flow turbulence
Bowen Yang, Yi Zhuang, Gökhan Yalnız +3
Depending on the type of flow, the transition to turbulence can take one of two forms: either turbulence arises from a sequence of instabilities or from the spatial proliferation o…
Optimal body force for heat transfer in turbulent vertical heated pipe flow
Shijun Chu, Elena Marensi, Ashley P. Willis
The vertical heated-pipe is widely used in thermal engineering applications, as buoyancy can help drive a flow, but several flow regimes are possible: shear-driven turbulence, lami…
Modelling the transition from shear-driven turbulence to convective turbulence in a vertical heated pipe
Shijun Chu, Elena Marensi, Ashley P. Willis
Heated pipe flow is widely used in thermal engineering applications, but the presence of buoyancy force can cause intermittency, or multiple flow states at the same parameter value…
Excitation and stability of nonlinear compressible Görtler vortices and streaks induced by free-stream vortical disturbances
Dongdong Xu, Pierre Ricco, Elena Marensi
We study the generation, nonlinear development and secondary instability of unsteady Görtler vortices and streaks in compressible boundary layers exposed to free-stream vortical d…
Laminarising turbulent pipe flow by linear and nonlinear optimisation
Shijun Chu, Ashley P. Willis, Elena Marensi
It has been observed that flattening the mean velocity profile of pipe flow by body force can laminarise turbulence, a promising means to reduce frictional drag substantially. To e…
The minimal seed for transition to convective turbulence in heated pipe flow
Shijun Chu, Ashley P. Willis, Elena Marensi
It is well known that buoyancy suppresses, and can even laminarise turbulence in upward heated pipe flow. Heat transfer seriously deteriorates in this case. Through a new DNS model…