Type of Inflow Calculation

Index Type of Inflow calculation Ver: 0

DESCRIPTION

A fully developed inlet velocity profile, calculated on the basis of the sub-task fluid model, is prescribed. The tangential velocity component vanishes; the flow rate (volume flow rate except for the gas problem where the mass flow rate is used instead) is specified by the user.

For non-isothermal flow problems and gas flow problems, a fully developed inlet temperature profile, calculated on the basis of the sub-task thermal model coupled with the fluid model, is prescribed. This option is available for the temperature when an inflow boundary condition has been selected for the momentum equation on the same boundary set.

For flow problems, the current value of the flow rate is recalled; a positive sign of the flow rate implies that the fluid enters the domain.

OPTIONS

1 Automatic

This leaves the choice to Polydata. 'Fully developed' is generally selected, unless one solves an inverse extrusion problem and the inlet is part of the constant section (parallel dies). In the latter case, 'Constant normal force' is chosen.

2 Fully developed

Polyflow will solve a fully developed flow problem before the main calculation. In 2D, Polyflow will solve a 1D problem along the segment. Similarly in 3D, Polyflow will calculate a fully developed channel flow problem in 2D. Polyflow will then impose the computed velocity profile as prescribed velocity during the main calculation.

3 Constant normal force

The normal force is prescribed (it is supposed constant on the section), the value being tantamount to obtain the prescribed flow rate. The value of the pressure is calculated by Polyflow and the velocity components are not prescribed during the main calculation.

NOTES

This boundary condition is not available in a 'Film model' sub-task (isothermal, non-isothermal or viscoelastic). One must impose the velocity components.

For many non-linear flow problems, it is interesting to increase the flow rate from a low to its nominal value.

This can be done by means of an evolution scheme. The current task should then be of the evolution type.

When introducing the volume(or mass) flow rate, the user should be aware of its dimensions. For 2-D planar flows, Q is a volume (or mass) flow rate per unit length in the transverse direction. For 2-D axisymmetric and 3-D problems, Q is the total volume (or mass) flow rate in the entry section.

The units for the volume flow rate Q are :

2-D planar

Parameter	Mass	Length	Time	Temperature
Q	0	2	-1	0

2-D axisymmetric and 3-D

Parameter	Mass	Length	Time	Temperature
Q	0	3	-1	0

The units for the mass flow rate Q are :

2-D planar

Parameter	Mass	Length	Time	Temperature
Q	1	-1	-1	0

2-D axisymmetric and 3-D

Parameter	Mass	Length	Time	Temperature
Q	1	0	-1	0

SEE ALSO

1	Automatic
	This leaves the choice to Polydata. 'Fully developed' is generally selected, unless one solves an inverse extrusion problem and the inlet is part of the constant section (parallel dies). In the latter case, 'Constant normal force' is chosen.
2	Fully developed
	Polyflow will solve a fully developed flow problem before the main calculation. In 2D, Polyflow will solve a 1D problem along the segment. Similarly in 3D, Polyflow will calculate a fully developed channel flow problem in 2D. Polyflow will then impose the computed velocity profile as prescribed velocity during the main calculation.
3	Constant normal force
	The normal force is prescribed (it is supposed constant on the section), the value being tantamount to obtain the prescribed flow rate. The value of the pressure is calculated by Polyflow and the velocity components are not prescribed during the main calculation.