KTMM Seminar:Laminar to Turbulence Transition in Sudden Expansion..
Merhabalar,
09 KASIM Perşembe günü, 13:40-14:30 saatleri arasında Kompozit Teknolojileri Mükemmeliyet Merkezinde, Prof.Mostafa Safdari Shadloo, Normandie Universty " LAMINAR TO TURBULENCE TRANSITION IN SUDDEN EXPANSION PIPE FLOWS" başlıklı seminer verecektir.
Sabancı Üniversitesi -Teknopark Gidiş
Teknopark- Sabancı Üniversitesi Dönüş
Araç Hareket Alanı : KTMM Binası Önü
Title: LAMINAR TO TURBULENCE TRANSITION IN SUDDEN EXPANSION PIPE FLOWS
Speaker: Prof.Mostafa Safdari Shadloo, Normandie Universty
Time: Nov..09, 2017, 13:40-14:30
Place: Teknopark- KTMM
Abstract:
Flow in a sudden expansion pipe is a basic fluid mechanics problem that has both fundamental and practical interests. One of the crucial issue in studying flow bifurcation and transition to turbulence in pipes is a gap of critical Reynolds number predicted by simulations and the one found in experiments. This gap is believed to be caused by the imperfections that are always present in the experiments. Beside the natural transition, which is difficult to predict, the simulations very often use finite-amplitude forced perturbations to trigger the transition. Better understanding of this “forced" turbulence state could help to understand the difference between experimental and numerical predictions. The recent numerical investigation of Sanmiguel-Rojas & Mullin [2] shows the existence of a hysteresis cycle when varying the Reynolds number (Re = U d/ν, with d the inlet diameter, U the mean inlet velocity and ν the kinematic viscosity) around its critical value. The extent of this hysteresis loop is surprisingly large (varying from Re = 1450 to 1850). The underlying mechanisms that govern the transition are far from being completely understood, and the transition mechanism is extremely sensitive to the shape and energy of the initial perturbation. Hence, one need to know how the transition occurs precisely and how long the system stands before laminar or turbulent states occur.
Biograph:
Dr. Shadloo is actively engaged in research in the fields of hydrodynamics, aerodynamics, turbulence, heat transfer and shock waves for the last 7 years. His expertise is mainly in theoretical and computational fluid dynamics, but has also been active in developing validation strategies and guidelines for computational fluid mechanics. He aims to develop a new generation high-order coupled algorithm for compressible/incompressible fluid flows with complex physical behaviors, in relation to industrial applications. In this framework he uses high-performance computing (HPC), high-fidelity direct numerical simulations (DNS) and large-eddy simulations (LES) to decipher complex instabilities and flow behaviors caused mainly by shocks and/or turbulent flows, with heat transfer and compressibility effects.
Dr. Shadloo is a guest editor of several highly prestigious national and international journals ( Computers and Fluids, Heat and Mass Transfer, Journal of Thermal Analysis and Calorimetry) and the reviewer of more than 50 national and international journals. He was also the Chairman of SPH session at the International Conference on Numerical Methods in Multiphase Flows, which was held in 2012 at Penn. State University, USA. At European level he has been the main investigator in numerous projects dealing with unsteady multiphysics flows including multidisciplinary modeling, simulation and validation. The main outcomes of Dr. Shadloo research are published as 37 original scientific articles/book chapter in highly prestigious peer-reviewed journals/books and 17 proceedings presented in international peer-reviewed conferences up to date.