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difference b/w ${TimeLevel} and ${Time} dependent variables

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Old   April 5, 2022, 09:00
Default difference b/w ${TimeLevel} and ${Time} dependent variables
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Raj Dasari
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Hello everyone,

I'm new in using star-ccm+ software. I have a doubt regarding field functions. I'm trying to ramp gravity in my simulation. For that i'm using field functions. While defining field function i have encountered two different dependent variables. they are ${TimeLevel} and ${Time}. Can anyone tell me what is the difference b/w these two dependent variables.

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Old   April 5, 2022, 09:30
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Time has units of seconds. For example, you start at a time of 0 seconds.


Time level is an index which keeps track of which solution is being handled (the current timestep, previous timestep , previous previous timestep, etc). In order lexicon, these would correspond to so-called solution levels n, n-1, n-2, etc.
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Old   April 5, 2022, 10:36
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Quote:
Originally Posted by LuckyTran View Post
Time has units of seconds. For example, you start at a time of 0 seconds.


Time level is an index which keeps track of which solution is being handled (the current timestep, previous timestep , previous previous timestep, etc). In order lexicon, these would correspond to so-called solution levels n, n-1, n-2, etc.
Thank you for your response. I have one more doubt, I'm using the adaptive time step for the simulation. So in this case if i use the time level variable then it will use the previous time step value for calculating the gravity?(i'm using this variable to define the gravity field function)

Can you tell me what i'm thing is right?
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Old   April 5, 2022, 12:01
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First, what is your gravity field function? How can we answer that without having any clue what your formula is?

Time level is a number.

If you have no idea what a field function is, I recommend you to not use it in your formula.


If you want the current time then Time is your friend. If you want the previous time then time - timestep is your friend.
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Old   April 6, 2022, 06:37
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Quote:
Originally Posted by LuckyTran View Post
First, what is your gravity field function? How can we answer that without having any clue what your formula is?

Time level is a number.

If you have no idea what a field function is, I recommend you to not use it in your formula.


If you want the current time then Time is your friend. If you want the previous time then time - timestep is your friend.
This is the field function def that i would like to use -1*min(9.81,${TimeLevel}*9.81/600). Can please tell me what timelevel (i mean the value of timelevel) will it take here. I want to ramp the gravity gradually. so please tell me how timelevel actually work here in this case.
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Old   April 7, 2022, 01:34
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Time level is a counter. When you start the simulation and initialize, it will be at 0. When you proceed to the next time, time level will be 1. And then 2. And then 3 and so on. It is the timestep equivalent of an iteration counter.


If your intent is to ramp up the gravity field from 0 to 600 timesteps, then yes time level could be used in this sense.
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