A proper-orthogonal-decomposition–based model for the wall layer of a turbulent channel flow

2009 ◽  
Vol 21 (1) ◽  
pp. 015111 ◽  
Author(s):  
Bérengère Podvin
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Wall Layer ◽  
Orthogonal Decomposition ◽  
Proper Orthogonal

scholarly journals Spatio-temporal proper orthogonal decomposition of turbulent channel flow

2019 ◽  
Vol 864 ◽  
pp. 614-639 ◽  
Author(s):  
Srikanth Derebail Muralidhar ◽  
Bérengère Podvin ◽  
Lionel Mathelin ◽  
Yann Fraigneau
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Channel Flow ◽  
Nonlinear Effects ◽  
Turbulent Channel Flow ◽  
Wall Layer ◽  
Orthogonal Decomposition ◽  
Closed Form Expression ◽  
Temporal Decomposition ◽  
Spatio Temporal ◽  
Proper Orthogonal

An extension of proper orthogonal decomposition is applied to the wall layer of a turbulent channel flow ($Re_{\unicode[STIX]{x1D70F}}=590$), so that empirical eigenfunctions are defined in both space and time. Due to the statistical symmetries of the flow, the eigenfunctions are associated with individual wavenumbers and frequencies. Self-similarity of the dominant eigenfunctions, consistent with wall-attached structures transferring energy into the core region, is established. The most energetic modes are characterized by a fundamental time scale in the range 200–300 viscous wall units. The full spatio-temporal decomposition provides a natural measure of the convection velocity of structures, with a characteristic value of 12$u_{\unicode[STIX]{x1D70F}}$ in the wall layer. Finally, we show that the energy budget can be split into specific contributions for each mode, which provides a closed-form expression for nonlinear effects.

Proper Orthogonal Decomposition of Turbulent Channel Flow

2001 ◽  
pp. 473-478 ◽  
Author(s):  
Giancarlo Alfonsi ◽  
Leonardo Primavera ◽  
Giuseppe Passoni ◽  
Carlo Restano
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Orthogonal Decomposition ◽  
Proper Orthogonal

PROPER ORTHOGONAL DECOMPOSITION: A TOOL TO STUDY THE UNDERLYING PHYSICS OF TURBULENCE

2017 ◽  
Vol 79 (7-3) ◽  
Author(s):  
Syed Mohd Yahya ◽  
Syed Fahad Anwer ◽  
Sanjeev Sanghi
Keyword(s):  
Proper Orthogonal Decomposition ◽  
Channel Flow ◽  
Average Energy ◽  
Turbulent Channel Flow ◽  
Dynamical Behaviour ◽  
Orthogonal Decomposition ◽  
Wall Structure ◽  
Eddy Simulation ◽  
Breaking Mechanism ◽  
Proper Orthogonal

Wall bounded turbulence have been investigated by many authors to understand the underlying physics, experimentally as well as numerically with different techniques and methods. Enormous studies are reported in the literature in the field of turbulence to get the insight of near wall structure in a broad spectrum of Reynolds number. To recognize the contribution of different turbulent scales in a flow a well-known technique, Proper Orthogonal decomposition (POD) is used. Dynamical behaviour of coherent structure in a turbulent channel flow submitted to high temperature gradient is investigated via proper orthogonal decomposition (POD). The turbulent data is generated using thermal large eddy simulation (TLES) of channel flow at Re = 180 for two values of temperature ratio between hot and cold wall. The POD technique is applied to fluctuating part of the velocity to study the temporal evolution of the most energetic modes. It is observed that dominant flow structures are elongated in streamwise direction which further distorted due to the interaction with bean shaped propagating modes. The plotted average energy E(t) as a function of non-dimensional time shows a constant level of fluctuating energy with one little peak at t+ = 1000, all other smaller spikes are showing constant fluctuations about mean line. This behavior at  quantitatively describe the role of temperature stratification which stabilizes the roll mode energy and prevent them from breakup into smaller scales thus affects the interaction process during turbulent burst event resulting in a chugging or relaminarizing phenomenon. It is observed that thermal stratification decreases the bursting rate by slowing the breaking mechanism of streamwise elongated modes to larger number of bean shaped modes which results in relaminarization of the flow near hot wall.

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