Random volume force along the line. More...

Collaboration diagram for Line tripping module:

Files
file	tripl.f
	Tripping function supporting conformal and AMR version of nek5000.

Functions
subroutine	tripl_register ()
	Register tripping module. More...

subroutine	tripl_init ()
	Initilise tripping module. More...

logical function	tripl_is_initialised ()
	Check if module was initialised. More...

subroutine	tripl_update ()
	Update tripping. More...

subroutine	tripl_forcing (ffx, ffy, ffz, ix, iy, iz, ieg)
	Compute tripping forcing. More...

subroutine	tripl_reset ()
	Reset tripping. More...

subroutine	tripl_1dprj ()
	Get 1D projection, array mapping and forcing smoothing. More...

subroutine	tripl_rphs_get
	Generate set of random phases. More...

real function	tripl_ran2 (il)
	A simple portable random number generator. More...

subroutine	tripl_frcs_get (ifreset)
	Generate forcing along 1D line. More...

Detailed Description

Random volume force along the line.

Set of routines to generate random volume force along the line defined by its starting and ending points. This tool can be used e.g. to mimic sand paper effect by setting a line running in a spanwise direction of the domain. Its aim is to introduce to the flow low amplitude random noise, that can be used to study e.g. a stability of a boundary layer.

Each line can be declared as finate in size (streatching from the starting point to the ending on) or the infinite one. The focing is applied only in the eliptical region along the line defined by the smoothing lengths SMTHX and SMTHY and rotated counterclockwise by ROTA angle. This angel is used as well to rotate the force, so it can be e.g. normal to the wall. In case of a finite length line the smoothing in the third direction SMTHZ is taken into account at the line ending points as well. The forcing is always normal to the line and its direction is not changin along the line. It is just forcing magnitude that fluctuates. As a line direction is specified by its starting and ending points, to determine the forcing direction we define line's local coordinate system build of three versors VX, VY and VZ, where VZ is by definition parallel to the line. To determine versors normal to the line we use vector cross product:

$VY = VZ \times VL,$

where VL is a vrsor parallel to the physical y axis for VZ parallel to the physical x axis, and it is parallel to the physical x axis otherwise. Finally

$VX = VZ \times VY.$

The last operation is a rotation of the local vresors VX and VY by ROTA angle along VZ versor. The forcing is always directed along VY versor.

The smoothing function is defined in the following way:

$\begin{eqnarray*} f_{smth}(r) = \left\{ \begin{array}{ll} exp\left(-r^2\right)*\left(1-r^2\right)^2 &\mbox{ if $r \leq 1.0$} \\ 0 &\mbox{ if $r > 1.0$} \end{array} \right. \end{eqnarray*}$

where

$r^2 = \left( {x_{loc} \over SMTHX} \right)^2 + \left( {y_{loc} \over SMTHY} \right)^2,$

for an infinite line and the interior of the finite line, and

$r^2 = \left( {x_{loc} \over SMTHX} \right)^2 + \left( {y_{loc} \over SMTHY} \right)^2 + \left( {z_{lrel} \over SMTHZ} \right)^2$

for the finite line endings. $x_{loc}$ and $y_{loc}$ are the point coordinates in the line's locall coordinate system, and $z_{lrel}$ is a third local coordinate relative to the corresponding line ending.

However, the function with limitted support can be easily replaced with simple Gauss profile (see commented lines in tripl_1dprj and notice factor 4.0 in the Gauss function necessary to make smoothing lenghts consistent with the original function). The tripping has both steady and unsteeady parts with amplitudes TIAMP and TDAMP respectively, and the forcing is given by:

$\begin{eqnarray*} f_x &=& f_{smth}(r)*f(z,t)*VY_x, \\ f_y &=& f_{smth}(r)*f(z,t)*VY_y, \\ f_z &=& f_{smth}(r)*f(z,t)*VY_z, \end{eqnarray*}$

where

$f(z,t) = TIAMP*g(z) + TDAMP*\left[ \left(1-b(t)\right)h^i(z) + b(t)h^{i+1}(z) \right],$

and

$\begin{eqnarray*} i &=& int(t/TDT), \\ b(t) &=& 3p^2-2p^3, \\ p &=& t/TDT -i. \end{eqnarray*}$

Here and are Fourier series of unit amplitude with NMODE random coefficients. The trip forcing generates noise with a uniform distribution over all frequencies lower than the cutoff frequency corresponding to $2\pi/TDT$ , where TDT is a time interval between change of the time dependent part of the trip.

This forcing has one continuous time derivative and is independent of the time discretisation. It should be independent as well on the simulation details (e.g. number of mpi ranks or restart flag). It is based on a similar implementation in the SIMSON code [2], and is described in detail in [7].

This tool can simulate number of lines with different set of parameters for each line. The maximal number of lines is given by tripl_nline_max in TRIPLD include file. In the same way maximal number of Fouries modes per line is given by tripl_nmode_max parameter. User has to adjust values of these variables before compilation of the code.

Module interface:

Global interface list:

Interface provided:

Global interface dependency:

Interface required:

multiple interfaces from Runtime parameters and Monitoring module modules
io_file_freeid from Input/output module module (debugging only)
math_rot3da from Math module

Module interface usage:: !======================================================================

subroutine userf (ix,iy,iz,ieg)

include 'SIZE'

include 'NEKUSE' ! FF[XYZ]

include 'PARALLEL' ! GLLEL

include 'SOLN' ! V[XYZ]

integer ix,iy,iz,ieg

ffx = 0.0

ffy = 0.0

ffz = 0.0

! add tripping

call tripl_forcing(ffx,ffy,ffz,ix,iy,iz,ieg)

return

end

!======================================================================

subroutine userchk

implicit none

include 'SIZE' !

include 'TSTEP' ! ISTEP, lastep, time

include 'INPUT' ! IF3D, PARAM

! start framework

if (istep.eq.0) call frame_start

! monitor simulation

call frame_monitor

! for tripping

call tripl_update

! finalise framework

if (istep.eq.nsteps.or.lastep.eq.1) then

call frame_end

endif

return

end

!======================================================================

subroutine frame_usr_register

implicit none

include 'SIZE'

include 'FRAMELP'

!-----------------------------------------------------------------------

! register modules

call tripl_register

return

end subroutine

!======================================================================

subroutine frame_usr_init

implicit none

include 'SIZE'

include 'FRAMELP'

include 'SOLN'

!-----------------------------------------------------------------------

! initialise modules

call tripl_init

return

end subroutine

!======================================================================

subroutine frame_usr_end

implicit none

include 'SIZE'

include 'FRAMELP'

!-----------------------------------------------------------------------

! finalise modules

return

end subroutine

!======================================================================

frame_monitor
subroutine frame_monitor
Simulataion monitoring.
Definition: frame.f:59

frame_start
subroutine frame_start
Start framework.
Definition: frame.f:12

frame_end
subroutine frame_end
Finalise framework.
Definition: frame.f:76

tripl_forcing
subroutine tripl_forcing(ffx, ffy, ffz, ix, iy, iz, ieg)
Compute tripping forcing.
Definition: tripl.f:376

tripl_register
subroutine tripl_register()
Register tripping module.
Definition: tripl.f:14

tripl_update
subroutine tripl_update()
Update tripping.
Definition: tripl.f:343

tripl_init
subroutine tripl_init()
Initilise tripping module.
Definition: tripl.f:136

Module parameters:

Global parameter list:: Parameters provided by tripl module (include file - TRIPLD):

Varaible	Type	Runtime parameter	Default value	Description
tripl_nline	integer	_tripl:nline	0	Number of tripping lines
tripl_tiamp(il)	real	_tripl:tiamp'il'	0.0	Time independent amplitude
tripl_tdamp(il)	real	_tripl:tdamp'il'	0.0	Time dependent amplitude
tripl_spos(1,il)	real	_tripl:sposx'il'	0.0	Starting point X of 'il' line
tripl_spos(2,il)	real	_tripl:sposy'il'	0.0	Starting point Y of 'il' line
tripl_spos(3,il)	real	_tripl:sposz'il'	0.0	Starting point Z of 'il' line
tripl_epos(1,il)	real	_tripl:eposx'il'	0.0	Ending point X of 'il' line
tripl_epos(2,il)	real	_tripl:eposy'il'	0.0	Ending point Y of 'il' line
tripl_epos(3,il)	real	_tripl:eposz'il'	0.0	Ending point Z of 'il' line
tripl_smth(1,il)	real	_tripl:smthx'il'	0.0	Smoothing length X of 'il' line
tripl_smth(2,il)	real	_tripl:smthy'il'	0.0	Smoothing length Y of 'il' line
tripl_smth(3,il)	real	_tripl:smthz'il'	0.0	Smoothing length Z of 'il' line
tripl_lext(il)	logical	_tripl:lext'il'	.F.	Line extension
tripl_rota(il)	real	_tripl:rota'il'	0.0	Rotation angle of 'il' line
tripl_nmode(il)	integer	_tripl:nmode'il'	0	Number of Fourier modes of 'il' line
tripl_tdt(il)	real	_tripl:tdt'il'	0.0	Time step for tripping of 'il' line

Module parameter usage:: [_TRIPL] # Runtime paramere section for tripping module

NLINE = 2 # Number of tripping lines

TIAMP01 = 0.00000000E+00 # Time independent amplitude

TDAMP01 = 1.00000000E+01 # Time dependent amplitude

SPOSX01 = 8.30000000E+00 # Starting pont X

SPOSY01 = 3.03500000E+00 # Starting pont Y

SPOSZ01 = 0.00000000E+00 # Starting pont Z

EPOSX01 = 8.30000000E+00 # Ending pont X

EPOSY01 = 3.03500000E+00 # Ending pont Y

EPOSZ01 = 4.50000000E+00 # Ending pont Z

SMTHX01 = 1.36000000E+00 # Smoothing length X

SMTHY01 = 0.34000000E+00 # Smoothing length Y

SMTHZ01 = 0.00000000E+00 # Smoothing length Z

LEXT01 = yes # Line extension

ROTA01 = 0.00000000E+00 # Rotation angle in radians

NMODE01 = 16 # Number of Fourier modes

TDT01 = 0.14000000E+00 # Time step for tripping

TIAMP02 = 0.00000000E+00 # Time independent amplitude

TDAMP02 = 1.00000000E+01 # Time dependent amplitude

SPOSX02 = 8.80000000E+00 # Starting pont X

SPOSY02 = 0.99430000E+00 # Starting pont Y

SPOSZ02 = 0.00000000E+00 # Starting pont Z

EPOSX02 = 8.80000000E+00 # Ending pont X

EPOSY02 = 0.99430000E+00 # Ending pont Y

EPOSZ02 = 4.50000000E+00 # Ending pont Z

SMTHX02 = 0.28000000E+00 # Smoothing length X

SMTHY02 = 0.07000000E+00 # Smoothing length Y

SMTHZ02 = 0.20000000E+00 # Smoothing length Z

LEXT02 = no # Line extension

ROTA02 = 0.12300000E+00 # Rotation angle in radians

NMODE02 = 76 # Number of Fourier modes

TDT02 = 0.14000000E+00 # Time step for tripping

Function Documentation

◆ tripl_1dprj()

subroutine tripl_1dprj

Get 1D projection, array mapping and forcing smoothing.

This routine supports straight lines given by their starting and ending points. Additional flagg allows to introuduce forcing periodicity or contain it between starting and ending points + smooting lenght in z

Remarks: This routine uses global scratch space CTMP0 and CTMP1

Definition at line 445 of file tripl.f.

References ifill(), rzero(), and sort().

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◆ tripl_forcing()

subroutine tripl_forcing	(	real	ffx,
		real	ffy,
		real	ffz,
		integer	ix,
		integer	iy,
		integer	iz,
		integer	ieg
	)

Compute tripping forcing.

Parameters

[in,out]	ffx,ffy,ffz	forcing; x,y,z component
[in]	ix,iy,iz	GLL point index
[in]	ieg	global element number

Definition at line 375 of file tripl.f.

References gllel().

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◆ tripl_frcs_get()

subroutine tripl_frcs_get ( logical ifreset )

Generate forcing along 1D line.

Parameters

[in] ifreset reset flag

Definition at line 687 of file tripl.f.

References cmult(), copy(), io_file_freeid(), and rzero().

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◆ tripl_init()

subroutine tripl_init

Initilise tripping module.

Note: This routine should be called in frame_usr_init

Definition at line 135 of file tripl.f.

References cross(), math_rot3da(), mntr_abort(), mntr_log(), mntr_logi(), mntr_logr(), mntr_logrv(), mntr_tmr_add(), mntr_warn(), rprm_rp_get(), rzero(), tripl_1dprj(), tripl_frcs_get(), and tripl_rphs_get().

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◆ tripl_is_initialised()

logical function tripl_is_initialised

Check if module was initialised.

Returns: tripl_is_initialised

Definition at line 329 of file tripl.f.

◆ tripl_ran2()

real function tripl_ran2 ( integer il )

A simple portable random number generator.

Requires 32-bit integer arithmetic. Taken from Numerical Recipes, William Press et al. Gives correlation free random numbers but does not have a very large dynamic range, i.e only generates 714025 different numbers. Set seed negative for initialization

Parameters

[in] il line number