[kendinemühendis]

How can i make ramp function for inlet? File etc.

[Tobermory]

Try something like uniformFixedValue, which allows a tabular input. If that's not what you are after, then you'll need to give us some more details on what you are trying to achieve ...

[kendinemühendis]

I want to create a speed value that varies with time.

For example;


time = 0 sec -> U (10 0 10)
time = 1 sec -> U ( 200 0 200 )

U speed will increase as a ramp function within 1 second. I'm drawing a graph as an example.

[IMG] https://resimlink.com/XmHvws13D [/IMG]

[Tobermory]

Try:

inlet {
    type                 uniformFixedValue;
    uniformValue    table
                           (
                              (0   (10 0 10))
                              (1   (200 0 200))
                           );
}

where "inlet" is the boundary patch name.

[foldandfly]

Alternatively, you can use a coded function within the U file:

inlet
{
        type            codedFixedValue;
        value           uniform (10 0 10);
        redirectType myFunction; // This specifies a name for the coded boundary condition
        code
        #{
            const scalar t = this->db().time().value();    // Current time
            const scalar rampDuration = 1.0;   // Duration for ramping (seconds)
            const scalar amplitude = 190;      // Amplitude of ramp function
            const scalar uInitial = 10;      // Velocity at t=0
        
            scalar ramp = min(t / rampDuration, 1.0); // Gradual ramp
            vector U_inlet = (uInitial + (ramp* amplitude)) * vector(1, 0, 1);
        
            operator==(U_inlet); // Apply velocity
        #};
}

[kendinemühendis]

Thank you! This worked but in the U file "internalField uniform (485.79 0 176.81); " I am having problems with this part. When I write "internalField uniform (450 0 150);" the analysis is solved, but when I write (485.79 0 176.81) it is not solved. What do you think could be the reason? Thank you very much.

Originally Posted by Tobermory

Try:

inlet {
    type                 uniformFixedValue;
    uniformValue    table
                           (
                              (0   (10 0 10))
                              (1   (200 0 200))
                           );
}

where "inlet" is the boundary patch name.

[kendinemühendis]

Thank you! I will try

Originally Posted by foldandfly

Alternatively, you can use a coded function within the U file:

inlet
{
        type            codedFixedValue;
        value           uniform (10 0 10);
        redirectType myFunction; // This specifies a name for the coded boundary condition
        code
        #{
            const scalar t = this->db().time().value();    // Current time
            const scalar rampDuration = 1.0;   // Duration for ramping (seconds)
            const scalar amplitude = 190;      // Amplitude of ramp function
            const scalar uInitial = 10;      // Velocity at t=0
        
            scalar ramp = min(t / rampDuration, 1.0); // Gradual ramp
            vector U_inlet = (uInitial + (ramp* amplitude)) * vector(1, 0, 1);
        
            operator==(U_inlet); // Apply velocity
        #};
}