Gravitational Field - Revision history

Nairnj: /* Gravity Commands */

2016-06-03T15:46:45Z

Gravity Commands

← Older revision		Revision as of 15:46, 3 June 2016
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	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.

	In scripted files, the three parameters can either by ~~a constant~~ or a [[User Defined Functions\|user-defined functions]] of position and time. Both should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9806.65,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.		In scripted files, the three parameters can either by constants or [[User Defined Functions\|user-defined functions]] of position and time. Both should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9806.65,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.

	In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.		In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.

Nairnj: /* Gravity Commands */

2016-06-02T02:34:35Z

Gravity Commands

← Older revision		Revision as of 02:34, 2 June 2016
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	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.

	In scripted files, the three parameters can either by a constant ~~(which currently must be in m/s<sup>2</sup>)~~ or a [[User Defined Functions\|user-defined functions]] of position and time. ~~If a function is used, it~~ should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.		In scripted files, the three parameters can either by a constant or a [[User Defined Functions\|user-defined functions]] of position and time. Both should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9806.65,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.

	In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.		In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.

Nairnj at 18:53, 13 January 2016

2016-01-13T18:53:39Z

← Older revision		Revision as of 18:53, 13 January 2016
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	== Gravity Commands ==		== Gravity Commands ==

	MPM simulations can include gravity or any other body forces~~, including~~ forces ~~that~~ depend on position and time. In scripted files, the command to add body forces is is:		MPM simulations can include gravity or any other body forces by forces on the grid. These forces can depend on position and time, although gravity is usually constant in a fixed reference frame. In scripted files, the command to add body forces is:

	Gravity <(bodyX)>,<(bodyY)>,<(bodyZ)>		Gravity <(bodyX)>,<(bodyY)>,<(bodyZ)>

	In <tt>XML</tt> files, body forces are added with ~~the the~~ <tt><Gravity></tt> element:		In <tt>XML</tt> files, body forces are added with a <tt><Gravity></tt> element:

	<Gravity>		<Gravity>
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	<BodyYForce>(gravY)</BodyYForce>		<BodyYForce>(gravY)</BodyYForce>
	<BodyZForce>(gravZ)</BodyZForce>		<BodyZForce>(gravZ)</BodyZForce>
	</Gravity>		</Gravity>

	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively. In axisymmetric calculations, the X and Y forces set the R and Z forces.

	(<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]], but in <tt>XML</tt> files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.

	~~== Grid Body Forces ==~~		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.

	~~Gravity~~ (~~in general~~) is a ~~constant~~ body force~~. The commands in this section let you apply a more general body force that can depend on position and time (currently only available~~ in [[~~OSParticulas~~]] ~~and then only when~~ using <tt>~~XML~~</tt> ~~commands). In~~ <tt>~~XML~~</tt> ~~files~~, ~~body forces are added within the~~ <tt>~~<Gravity>~~</tt> ~~element:~~

	~~<Gravity>~~
	~~<GridBodyXForce>~~(~~bodyX~~)~~</GridBodyXForce>~~
	~~<GridBodyYForce>~~(~~bodyY~~)~~</GridBodyYForce>~~
	~~<GridBodyZForce>(bodyZ)</GridBodyZForce>~~
	~~</Gravity>~~

			In scripted files, the three parameters can either by a constant (which currently must be in m/s<sup>2</sup>) or a [[User Defined Functions\|user-defined functions]] of position and time. If a function is used, it should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.

	~~You~~ can ~~use both~~ [[~~#Gravity Commands~~\|~~constant gravity~~]] ~~commands and grid body force functions in the same input commands~~. ~~When both are used,~~ the ~~resulting body force~~ is ~~the sum of the two forces. When body forces are~~ constant, it is more efficient to ~~use [[#Gravity Commands\|~~constant ~~gravity]] commands than~~ to ~~use~~ body ~~force functions~~.		In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.

Nairnj at 18:38, 13 January 2016

2016-01-13T18:38:52Z

← Older revision		Revision as of 18:38, 13 January 2016
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	MPM simulations can include gravity or any other body forces, including forces that depend on position and time. In scripted files, the command to add body forces is is:		MPM simulations can include gravity or any other body forces, including forces that depend on position and time. In scripted files, the command to add body forces is is:

	Gravity <(~~gravX~~)>,<(~~gravX~~)>,<(~~gravX~~)>		Gravity <(bodyX)>,<(bodyY)>,<(bodyZ)>

	In <tt>XML</tt> files, ~~gravity is~~ added with the the <tt><Gravity></tt> element:		In <tt>XML</tt> files, body forces are added with the the <tt><Gravity></tt> element:

	<Gravity>		<Gravity>
			<GridBodyXForce>(bodyX)</GridBodyXForce>
			<GridBodyYForce>(bodyY)</GridBodyYForce>
			<GridBodyZForce>(bodyZ)</GridBodyZForce>
	<BodyXForce>(gravX)</BodyXForce>		<BodyXForce>(gravX)</BodyXForce>
	<BodyYForce>(gravY)</BodyYForce>		<BodyYForce>(gravY)</BodyYForce>
	<BodyZForce>(gravZ)</BodyZForce>		<BodyZForce>(gravZ)</BodyZForce>
	</Gravity>		</Gravity>

			where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively. In axisymmetric calculations, the X and Y forces set the R and Z forces.

	~~where <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt> are the accelerations due to gravity in the x, y, and z directions, respectively~~ (<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]], but in <tt>XML</tt> files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].		(<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]], but in <tt>XML</tt> files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.		In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.
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	</Gravity>		</Gravity>

	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.		You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.

Nairnj: /* Gravity Commands */

2016-01-13T18:34:48Z

Gravity Commands

← Older revision		Revision as of 18:34, 13 January 2016
Line 2:		Line 2:
	== Gravity Commands ==		== Gravity Commands ==

	MPM simulations can include gravity or any other ~~constant~~ body forces. In scripted files, the command to add ~~gravity~~ is:		MPM simulations can include gravity or any other body forces, including forces that depend on position and time. In scripted files, the command to add body forces is is:

	Gravity <(gravX)>,<(gravX)>,<(gravX)>		Gravity <(gravX)>,<(gravX)>,<(gravX)>

Nairnj at 23:52, 2 June 2015

2015-06-02T23:52:09Z

← Older revision		Revision as of 23:52, 2 June 2015
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	</Gravity>		</Gravity>

	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in ~~units of~~ [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.		You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.

Nairnj at 22:50, 2 June 2015

2015-06-02T22:50:20Z

← Older revision		Revision as of 22:50, 2 June 2015
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	</Gravity>		</Gravity>

	where <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt> are the accelerations due to gravity in the x, y, and z directions, respectively (<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are ~~m/sec<sup>2</sup>~~, but in <tt>XML</tt> files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].		where <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt> are the accelerations due to gravity in the x, y, and z directions, respectively (<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]], but in <tt>XML</tt> files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.		In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.

Nairnj at 21:40, 2 June 2015

2015-06-02T21:40:50Z

← Older revision		Revision as of 21:40, 2 June 2015
Line 14:		Line 14:
	</Gravity>		</Gravity>

	where <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt> are the accelerations due to gravity in the x, y, and z directions, respectively (<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are m/sec<sup>2</sup>, but in <tt>XML</tt> files, the units are ~~mm/sec<sup>2</sup>~~.		where <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt> are the accelerations due to gravity in the x, y, and z directions, respectively (<tt>(gravX)</tt> and <tt>(gravY)</tt> are for R and Z directions in axisymmetric calculations). In scripted files, the units are m/sec<sup>2</sup>, but in <tt>XML</tt> files, the units are [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.		In scripted files, all three parameters are optional. If all are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If <tt>(gravX)</tt> is included, but <tt>(gravY)</tt> and/or <tt>(gravZ)</tt> are omitted, the omitted parameters will be set to zero. But, if no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have Earth's gravity you need a <tt>Gravity</tt> command, even if it has no parameters. In <tt>XML</tt> files, any omitted forces are set to zero.
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	</Gravity>		</Gravity>

	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in units of ~~mm/sec<sup>2</sup>~~.		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in units of [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]].

	You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.		You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.

Nairnj: /* Grid Body Forces */

2015-03-21T17:18:22Z

Grid Body Forces

← Older revision		Revision as of 17:18, 21 March 2015
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	</Gravity>		</Gravity>

	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in units of mm/<sup>2</sup>.		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in units of mm/sec<sup>2</sup>.

	You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.		You can use both [[#Gravity Commands\|constant gravity]] commands and grid body force functions in the same input commands. When both are used, the resulting body force is the sum of the two forces. When body forces are constant, it is more efficient to use [[#Gravity Commands\|constant gravity]] commands than to use body force functions.

Nairnj: /* Grid Body Forces */

2014-09-19T10:01:31Z

Grid Body Forces

← Older revision		Revision as of 10:01, 19 September 2014
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	== Grid Body Forces ==		== Grid Body Forces ==

	Gravity (in general) is a constant body force. The commands in this section let you apply a more general body force that can depend on position and time (currently only available in [[OSParticulas]] and using <tt>XML</tt> commands). In <tt>XML</tt> files, body forces are added within the <tt><Gravity></tt> element:		Gravity (in general) is a constant body force. The commands in this section let you apply a more general body force that can depend on position and time (currently only available in [[OSParticulas]] and then only when using <tt>XML</tt> commands). In <tt>XML</tt> files, body forces are added within the <tt><Gravity></tt> element:

	<Gravity>		<Gravity>

← Older revision		Revision as of 15:46, 3 June 2016
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	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.

	In scripted files, the three parameters can either by ~~a constant~~ or a [[User Defined Functions\|user-defined functions]] of position and time. Both should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9806.65,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.		In scripted files, the three parameters can either by constants or [[User Defined Functions\|user-defined functions]] of position and time. Both should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9806.65,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.

	In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.		In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.

← Older revision		Revision as of 02:34, 2 June 2016
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	where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.		where <tt>(bodyX)</tt>, <tt>(bodyY)</tt>, and <tt>(bodyZ)</tt> are [[User Defined Functions\|user-defined functions]] of position and time that evaluate to a body force acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. In XML files, the body forces can alternatively be entered using <tt>(gravX)</tt>, <tt>(gravY)</tt>, and <tt>(gravZ)</tt>, but these must be constant (by numeric value) accelerations due to gravity in the x, y, and z directions, respectively (in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]). In axisymmetric calculations, the X and Y forces set the R and Z forces.

	In scripted files, the three parameters can either by a constant ~~(which currently must be in m/s<sup>2</sup>)~~ or a [[User Defined Functions\|user-defined functions]] of position and time. ~~If a function is used, it~~ should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9.8,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.		In scripted files, the three parameters can either by a constant or a [[User Defined Functions\|user-defined functions]] of position and time. Both should evaluate to acceleration in [[ConsistentUnits Command#Legacy and Consistent Units\|acceleration units]]. All three parameters are optional. If any are omitted, the gravitational force field is set to Earth's gravity with down being in the negative y direction (''i.e.'', it is equivalent to the command <tt>Gravity 0,-9806.65,0</tt>). If no <tt>Gravity</tt> command is used at all, the simulation will have no gravitational forces. Thus to have the default Earth's gravity you still need a <tt>Gravity</tt> command, even if it has no parameters.

	In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.		In <tt>XML</tt> files, you can enter [[User Defined Functions\|user-defined functions]] or constant values. If the desired result is a constant acceleration, it is more efficient to enter using <tt>(gravX)</tt>, <tt>(gravY)</tt>, or <tt>(gravZ)</tt> then to enter a function with a constant value (because it avoids needless function evaluations for each node). If you enter both constant values and functions, the two are added to get total body forces. Any omitted forces are set to zero.