block initialize command


block initialize keyword <range>

Primary keywords:

extra    rvelocity    rvelocity-x    rvelocity-y    rvelocity-z    velocity    velocity-x    velocity-y    velocity-z

Initialize the velocity or extra variable a rigid block. Velocities are applied to the centroids of rigid blocks. The range over which the item is applied can be limited by providing a range.

extra <i > a<[blockinitializeblock]>

Set block extra variable in slot \(i\) to a. If not given, the default slot is 1

rvelocity v <[blockinitializeblock]>

Set initial rotational velocity to v.

rvelocity-x f <[blockinitializeblock]>

Set x-component of the rotational velocity.

rvelocity-y f <[blockinitializeblock]>

Set y-component of rotational velocity .

rvelocity-z f <[blockinitializeblock]>

Set z-component of rotational velocity.

velocity v <[blockinitializeblock]>

Set initial velocity in the \(x\)-, \(y\)-, and \(z\)-directions to v.

velocity-x f <[blockinitializeblock]>

Set initial velocity in the \(x\)-direction.

velocity-y f <[blockinitializeblock]>

Set initial velocity in the \(y\)-direction.

velocity-z f <[blockinitializeblock]>

Set initial velocity in the \(z\)-direction.

block initialize Keyword Block

The following keywords may be used to modify a supplied value. If the description of the modifier keyword mentions what type of value it may be applied to (e.g., scalar value, vector value, etc.), be sure there is a match between the modifier and the main keyword value.

The keywords below are applicable to each of the following keywords of the block initialize command: extra, rvelocity, rvelocity-x, rvelocity-y, rvelocity-z, velocity, velocity-x, velocity-y and velocity-z.


Add the specified value to the existing value.

gradient v <origin v >

Apply a gradient to the scalar-value provided.


Specify that the value supplied for the keyword is in the local coordinate system of the gridpoint (if any). By default values are initialize in the global system.

This keyword cannot be used with the following keywords of the block initialize command: extra.


Multiply the existing value by the specified value.

vary v

Apply a linear variation to the scalar-value provided. Set initial velocity in the \(z\)-direction.