About gravity in operating conditions

ravi_adepu · September 9, 2009, 05:05

Dear All,

Could you please explain about gravity considerations in fluent.

1). If my y-direction is upwards and the fluid is flowing downwards, which sign i have to take ?

2). If my y-direction is upwards and the fluid is entering in upward direction(not exactly vertical) initially after that it flows downwards, which sign i have to take ?

Philipov · September 9, 2009, 06:20

See axes in your GAMBIT (for example) end orient the gravity force sign.
For example: Imagine you drop a stone, so you have "z" axis starting from the floor. The gravity force is "Z"=-9.81.... m/s2 opposite to the axis.

srjp · September 9, 2009, 08:22

The definition of gravity does not depend on your flow direction. It depends only on your coordinate axis system. The fluid may enter or leave anywhere, but gravity is only acting in one direction.

In your case, if 'y' direction is upwards, then gravity will be x = 0, y = -9.81, z = 0.

This is same for both your questions.

September 9, 2009, 05:05	About gravity in operating conditions	#1
ravi_adepu New Member ravi Join Date: Aug 2009 Posts: 5 Rep Power: 16	Dear All, Could you please explain about gravity considerations in fluent. 1). If my y-direction is upwards and the fluid is flowing downwards, which sign i have to take ? 2). If my y-direction is upwards and the fluid is entering in upward direction(not exactly vertical) initially after that it flows downwards, which sign i have to take ? rajann_786 likes this.

September 9, 2009, 06:20		#2
Philipov Senior Member Svetlin Filipov Join Date: Mar 2009 Location: United Kingdom Posts: 176 Rep Power: 17	See axes in your GAMBIT (for example) end orient the gravity force sign. For example: Imagine you drop a stone, so you have "z" axis starting from the floor. The gravity force is "Z"=-9.81.... m/s2 opposite to the axis. rajann_786 likes this.

September 9, 2009, 08:22		#3
srjp Member JP Join Date: Mar 2009 Posts: 57 Rep Power: 18	The definition of gravity does not depend on your flow direction. It depends only on your coordinate axis system. The fluid may enter or leave anywhere, but gravity is only acting in one direction. In your case, if 'y' direction is upwards, then gravity will be x = 0, y = -9.81, z = 0. This is same for both your questions. rajann_786 and haitham osman like this.

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