Dear Brad and members,
I've been doing an experiment recently to compare and contrast the Kwave simulation.
My experiments are mainly as follows:
Using single emitting pulse concave spherical transducer, and through the layers of pork tissue (skin, fat, muscle) focus, I try to make the simulation and experiment conditions, such as emission signal corresponding to the first I won the transducer by the radial force balance method measuring the acoustic power, and then divided by the surface area (with transducer upper tangent circle area) to get the surface sound intensity, and get the simulation input pressure SQRT (I rho c), but the problem is coming, I get under the same conditions of the simulation and experimental results are not consistent, especially for the size of the focal point, simulation of the focal length is 2.02 cm,
However, the experimental result is 2.72cm, and the focal sound pressure has a good corresponding relationship.
The second question is, why do I get a smooth distribution of sound pressure in the radial sound axis in the simulation, and there is no side lobe, there is only one peak, but there is a side lobe in the experiment? I want to know why, is it related to my excitation signal?My signal is going to look something like this:
source_strength = 0.10953e6; % [Pa]
tone_burst_freq = 1e6 ; % [Hz]
tone_burst_cycles = 50;
signal_offsets=0;
input_signal = source_strength*toneBurst(1/kgrid.dt, tone_burst_freq, tone_burst_cycles,'Envelope','Rectangular','Plot', true,'SignalLength',kgrid.Nt,'SignalOffset', signal_offsets);
source.p = input_signal;The last question I want to know is the function of sensor. Record_start_index in processing pulse signal simulation. I have a preliminary understanding that it can collect data after the sound field reaches a stable state.
What variable does that relate to?
We look forward to your early reply. Thank you