Lower Height Function Constants#
Lower Height Function Constants = {model_name} <floatlist>
Description / Usage#
This card takes the specification of the lower-height function for the confined channel lubrication capability, or the lub_p equation. This function specifies the height of the channel versus distance and time. Currently three models for {model_name} are permissible:
CONSTANT_SPEED |
This model invokes a squeeze/separation velocity uniformly across the entire material region, viz. the two walls are brought together/apart at a constant rate. This option requires two floating point values
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ROLL_ON |
This model invokes a squeeze/separation velocity in a hinging-motion along one boundary. The model is best explained with the figure in the technical discussion section. The equation for the gap h as a function of time and the input parameters (floats) is as follows:
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ROLL |
This model is used for a roll coating geometry. This option requires 8 floats:
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TABLE <integer1> <character_string1> {LINEAR | BILINEAR} [integer2] [FILE = filenm] |
Please see discussion at the beginning of the material properties Chapter 5 for input description and options. Most likely character_string1 will be LOWER_DISTANCE This option is good for inputing table geometry versus distance. Specifically, an arbitrary lower height function model is input as a function of the x-direction coordinate of the Lower Velocity Function model. This option in turn requires the use of SLIDER_POLY_TIME lower velocity function model. See example below. |
Examples#
Following is a sample card:
Lower Height Function Constants = CONSTANT_SPEED {v_sq = -0.001} {h_i=0.001}
This results in an lower wall speed of 0.001 in a direction which reduces the gap, which is initial 0.001.
In another example:
Lower Height Function Constants = TABLE 2 LOWER_DISTANCE 0 LINEAR FILE=shell.dat
where shell.dat is a table with 2 columns, the first the position, the second the height.
Technical Discussion#
The material function model ROLL_ON prescribes the squeezing/separation motion of two non-parallel flate plates about a hinge point, as shown in the figure below.