Laminar-turbulent transition in pipes with body forces: continuous, discontinuous or both?
Date:
The laminar-turbulent transition in straight pipes is believed to occur through a continuous non-equilibrium phase transition in the directed percolation universality class. However, in curved pipes or in the presence of body forces it is possible to observe a discontinuous transition and other phenomenology which seem inconsistent with the emerging consensus. Here, we consider the perturbing effects of body forces and incorporate them into a minimal Landau theory of the transition. We calculate the phase diagram as a function of Reynolds number and body force strength, and show that above a threshold strength of the latter, there is a tricritical point which accounts for the observed discontinuity behavior, including spatially heterogeneous states. Our results are consistent with recent experiments in centrifugal pipes and direct numerical simulations of heated flows.
Presenter: Guru K Jayasingh (University of California, San Diego) Author: Nigel Goldenfeld (University of California, San Diego) Location: Monday March 17, Session MAR-A65 (Pattern Formation and Phase Transitions), Anaheim Hilton, Rendondo (Level 4)