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Clarification of expression : (acos(tpf.intnormr)) [Capillary filling]
Posted 18.03.2014, 08:59 GMT-4 Microfluidics Version 4.4 1 Reply
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i'm planning to model the capillary filling of different geometries. As introduction i've been studying the example from comsol : microfluidics module --> Two-Phase-Flow --> Capillary filling ls
under definitions/variables 1a there is the expression for theta : (acos(tpf.intnormr))[1/deg]
Can anyone explain to me how this expression is set up ?
cause 1 : i can't find the theta anywhere else in the model (the contact angle is later on defined as 3/8*pi rad)
and 2: if i try to use this expression in my own model it won't accept it.
hope you can help me out.
regards,
Remco
Hello Remco Vos
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'intnormr' is defined in 'Filling of a Capillary Channel—Phase Field' example. Look for it in documentation.
It looks like that:
Name Expression Unit Description
intnormr d(phipf,r)/sqrt(d(phipf,r)^2+d(phipf,z)^2+eps) Interface normal, r component
theta (acos(intnormr))[1/deg] rad Contact angle