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sorry forgot to say that results obtained are not reasonable at all. should I define a variable or parameter first?
the table basically is the far-field temp profile in y direction.
I also tried int1(y[1/m]) in the boundary condition but did not work either.

ASAL

Hi

read carefully how to treat temperatures, in absolute and relative, the difficulty in the beginning is the units when to consider ir relative hence for DT [K] == [degC] but when considering it in absolute T0[K] = T0[degC]+273.15

if you have a material interpolation function that isusing T0 in absolute but based on °C you should write int1(T[1/degC]) as for COMSOl, by default in SI T is in Kelvin, by writing it with the previous 1/units you get a numerical value transformed into Celsius and from which the units are removed, this is the standard way to enter an argument to an operator that motly do not expect units. If your int1 of T is based on Kelvin values you should write int1(T[1/K]), its with or without the asolute offset of 273.15

int1(y[1/m]) is something else, but again, what is int1 doing ? here you provide the Y coordinate in number as per meter (but with units removed). Is you interpolation function argument supposed to be a spatial dimension or a temperature (I'm wundering if its T out for position in hence intop1(y[1/m])*1[degC] or *1[K], note this is not the same

Conclusion check what you are doing with temperatures its easy to get it offset as input or as output ;)

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Good luck
Ivar

thanks a lot Ivar.

my table consists of depth (t) and temperature (f(t)) in Celsius and is called int1. the function argument is depth (y).

Hi

when I work on these functions with temperature, I mostly make an analytical function of the full expression I use in the BC field, and plot it with the plot command to be sure the unit transformation is handled correctly. Thereafter my simulations results are also mostly correct

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Good luck
Ivar

Hi Ivar,
even if I define the function analytically and get rid of the table it doesn't make any difference and when i want to define the BC, it is still not defined.
i thought it should be much easier that these as explained in the manual. defining either a table or a function and using it in the BC accordingly.

Hi

indeed it should be straightforward, you can set the units in the interpolation function (lower part of the tab

Is it something like this ? I have two "int" one in kelvin and one in degC, if you define the units in the interpolation function you do not need to use the y[1/m] and *1[K] when calling the function

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Good luck
Ivar

thanks Ivar. it worked.
i just defined the units in the function definition (units for argument and function) and recalled the function in the BC.

thanks for being helpful to comsol users.

ASAL