Acoustic impedance Plot

[Andrex_ITA]

All,

I'm trying to plot a graph of real and imaginary part of the acoustic impedance of an empty tube with a closed end.

This is the function of the Impedance and the graph I obtain:

[Andrex_ITA]

and this is what I expected:

[Andrex_ITA]

Thank you very much if everyone can help me, I'm becoming half crazy tryng to obtain something similar to what I expect.

[LucMeekes]

Attach you worksheet please. (See announcement to the right of this for instructions).
Mathcad will not plot imaginary parts of complex numbers. You need to use the Re () and Im () functions to separate the real and imaginary parts.

Success!
Luc

[JK_9625275]

Mathcad can plot real and imaginary or magnitude and phase.  I have attached an example where the acoustic reflection is at oblique angles.  I've used Mathcad 14 for the calculations.

[LucMeekes]

That's my point.

You are showing the use of Re() and Im() functions.

The Im() function takes any complex number and converts it's imaginary part into a real number. And that can be plotted, (only) because it's a real number.

Luc

[-MFra- · Accepted solution]

Hi, 

I used Mathcad 15 and I changed the data, to fit  to the graph you provided.

[Andrex_ITA]

Solved! Thank you very much!

I think I can't use the arg() function with the express version of prime 4.0, but at least I can plot the modulus correctly!

[Werner_E]

You are right. Re(), Im() and arg() are considered "Premium" functions and are not available in Express.

Fortunately the conjugate complex operator is not "Premium" and so you can easily define those "Premium" functions yourself in Prime Express:

[Andrex_ITA]

Thank you very much, I really appreciate it.

This is a super community!

Andrea

[Werner_E]

What your picture shows is that you have plotted the magnitude |Z(omea)| over omega.

But what you ant to see ist the plot of Re(Z(omea)) and Im(Z(omea)). So simply write those expression instead of |Z(omea)|.

You can see it done in MC15 in Francescos answer above. Re() and Im() are built-in functions you can use out of the box.

Some additional remarks:

.) You have better control over the step width of omega in the plot if you define a range variable for omega

.) You may consider using units as well - thats what Mathcad and even Prime is really good at.