[Gilsuss]

Hi All,

I am currently running a simulation case where I need to create a variable to let me turn on or off a heat source.
Basically, I have a preditive function where it tells the heat source to turn on or off, but after the function says to the heat source to turn off, it needs to wait more t_limit time before turning off.

Basically:
1. Heat_Status=On && Heat_Source=On
2. Predictive_function turns Heat_Status=Off
3. Heat_Source=On for more t_limit time
4. Heat_Status=Off && Heat_Source=Off

These 2 field functions, Heat_Status and Heat_Source, are not exclusively time dependent, but also depend on other parameters, like the temperature on the sensor.

The problem here is on the t_limit. I need some way to create this delay for turning it off.

I've thought about creating a variable for this case, but Star-ccm+ doesn't have variable creation options, only field functions, and in this case I would need to count the time after the Heat_Status funtion is turned off.

Would you have any ideas for this case?
Is there a way to create variables inside the software?
Or maybe a way around this problem?

Anyways, thank you for your time and patience.

[koful]

Hi,

If I understand correctly, you want to add a signal delay to heat source. What do you mean star can not create variable? It should be. Under the parameters folder you can create a delta time variable. Also at reports, you can create a simulation time report and add it to your function with adding a delta_time.

[cwl]

Originally Posted by Gilsuss

The problem here is on the t_limit. I need some way to create this delay for turning it off.

I've thought about creating a variable for this case, but Star-ccm+ doesn't have variable creation options, only field functions, and in this case I would need to count the time after the Heat_Status funtion is turned off.

Could be done with Simulation Operations and storing values of time in Parameters.

Could also be done with Update Events triggering Reports/Monitors to store values of time.

[Gilsuss]

Originally Posted by koful

Hi,

If I understand correctly, you want to add a signal delay to heat source. What do you mean star can not create variable? It should be. Under the parameters folder you can create a delta time variable. Also at reports, you can create a simulation time report and add it to your function with adding a delta_time.

What I mean is that Star-ccm+ can create parameters, but those parameters cannot update themselves alone without anything external of it, and also reports and field functions cannot update them.
I could also do the time tracking with reports, but if the heat source needs to be turned on and off continuously, the solution with reports will also not work.

The question that I have here is what external mechanisms I could use for storing this time information!

Originally Posted by cwl

Could be done with Simulation Operations and storing values of time in Parameters.

Could also be done with Update Events triggering Reports/Monitors to store values of time.

I will try exploring a solution using Update Events, but I still haven't worked with it. Could you show me a path to follow? Maybe a good workflow to use?

Thank you in advance!

[Voluped]

Create Field Functions:
Heat_Status: This function determines whether the heat source should be on or off based on the predictive function and sensor temperature.
Heat_Source: This function will incorporate the delay mechanism.

Define Heat_Status:
Create a field function (e.g., Heat_Status) that determines whether the heat source should be on or off based on the predictive function and sensor temperature.

Define a Time-Dependent Heat_Source:
Create a field function for Heat_Source that will use the value of Heat_Status and incorporate the delay mechanism. You can use a combination of logical conditions and a time-dependent field function.

Example Implementation:
// Define an initial state for the heat source
initialHeatSource = 1; // Assume the heat source starts as on

// Define the delay time (t_limit)
t_limit = 10; // Replace with your desired delay time

// Define the Heat_Status field function
Heat_Status = ... // Your predictive function based on sensor temperature

// Define the time-dependent Heat_Source field function
Heat_Source = if(Heat_Status == 0,
if(time - switchOffTime < t_limit, 1, 0),
1);

// Define the switchOffTime field function to capture the time when Heat_Status turns off
switchOffTime = if(Heat_Status == 0 && previousHeatStatus == 1, time, switchOffTime);

// Define the previousHeatStatus field function to keep track of the Heat_Status in the previous time step
previousHeatStatus = Heat_Status;

Implement the Field Functions:
Go to Tools > Field Functions and create the necessary field functions using the expressions provided above.
Ensure the Heat_Source field function correctly references the delay logic.

Apply the Field Functions:
Assign the Heat_Source field function to control the heat source in your simulation setup.