peclet::flow::Solver< Grid >::OutflowBackflow Struct Reference

OUTFLOW REVERSAL CENSUS – the regime in which the zero-gradient (do-nothing) outflow is only conditionally energy-stable. More...

#include <flow_ibm.hpp>

Public Attributes
double	maxReverse = 0.0
double	fraction = 0.0
double	energyInflux = 0.0
long	reversed = 0
long	total = 0

Detailed Description

template<class Grid>
struct peclet::flow::Solver< Grid >::OutflowBackflow

OUTFLOW REVERSAL CENSUS – the regime in which the zero-gradient (do-nothing) outflow is only conditionally energy-stable.

Over every rank-owned outflow face plane (the boundary normal-velocity plane; the tangential components are the boundary-adjacent inner cell's): maxReverse = max(0, -u.n) the largest reversed normal velocity, fraction = reversed faces / outlet faces, energyInflux = sum_reversed rho |u.n| |u|^2 / 2 (per unit area; h = 1). The last is the kinetic-energy production the do-nothing outlet admits where the flow re-enters (Esmaily-Moghadam, Bazilevs & Marsden 2011): a reversed face advects the ghost value – with the zero-gradient ghost, the boundary cell's own – back in, so the outlet-adjacent momentum row has an advective source with no sink. The backflow stabilization (applyBackflowStab) adds beta rho |u.n| to that row's diagonal, i.e. removes beta rho |u.n| |u_n|^2 of it; the analysis' unconditional bound is beta >= 1/2. Measured on the BFS whose bubble reaches the outlet (S = 16, Re_S = 800, x_r = L, 6000 steps): a transient excursion of max|u| to 1.28x the inlet peak ON the outlet column, bounded and finite with beta = 0 (1.909) and with the default 0.2 (1.897) alike – so at that Re the stabilization does not decide boundedness; the census is what tells you the regime is active. Distributed: reduced over the communicator (every rank must call it).

Definition at line 1245 of file flow_ibm.hpp.

Member Data Documentation

maxReverse

template<class Grid >

double peclet::flow::Solver< Grid >::OutflowBackflow::maxReverse = 0.0

Definition at line 1246 of file flow_ibm.hpp.

fraction

template<class Grid >

double peclet::flow::Solver< Grid >::OutflowBackflow::fraction = 0.0

Definition at line 1246 of file flow_ibm.hpp.

energyInflux

template<class Grid >

double peclet::flow::Solver< Grid >::OutflowBackflow::energyInflux = 0.0

Definition at line 1246 of file flow_ibm.hpp.

reversed

template<class Grid >

long peclet::flow::Solver< Grid >::OutflowBackflow::reversed = 0

Definition at line 1247 of file flow_ibm.hpp.

total

template<class Grid >

long peclet::flow::Solver< Grid >::OutflowBackflow::total = 0

Definition at line 1247 of file flow_ibm.hpp.

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The documentation for this struct was generated from the following file:

• src/flow_ibm.hpp