Resonator.jl

using MultipleScattering
using Plots

# The four parameters below are all the required dimensions of the resonator.
cavity_radius = 1.0;
cavity_length = 2.5;
mouth_radius = 0.3;
mouth_length = 0.5;


# Define positions of the particles constituting the resonator
radius = .1; # radius of the particles
d_particle = 2.001*radius; # distance between centers
# define the cavity of the resonator 
cavity_up = [[x,cavity_radius+radius] for x=radius:d_particle:cavity_length];
cavity_down = [[x,-cavity_radius-radius] for x=radius:d_particle:cavity_length]
cavity_right = [[cavity_length+.05*radius,y] for y=(-cavity_radius-radius):d_particle:(cavity_radius+2*radius)]

# define the mouth of the resonator
mouth_connect_down = [[radius-d_particle,y] for y=(-cavity_radius-radius):d_particle:(-mouth_radius)]
mouth_connect_up = [[radius-d_particle,y] for y=(mouth_radius+radius):d_particle:(cavity_radius+2*radius)]
mouth_up = [[x,mouth_radius+radius] for x = radius-2*d_particle:-d_particle:-mouth_length-radius]
mouth_down = [[x,-mouth_radius-radius] for x = radius-2*d_particle:-d_particle:-mouth_length-radius]

# put the different pieces together
X = [cavity_up;cavity_down;cavity_right;mouth_connect_down;mouth_connect_up;mouth_up;mouth_down];
X = [x - [cavity_length/2,cavity_radius/2-0.5] for x in X];


# Build the resonator
particle_medium =  Acoustic(2; ρ = 0., c = 0.);
Resonator = [Particle(particle_medium, Circle(x, radius)) for x in X];
plot(Resonator)
# savefig("Resonator.png")


# simulate the scattered fields for incoming plane waves of different frequencies
host_medium = Acoustic(2; ρ=1.0, c=1.0); # medium of the background, 2 is the dimension of the setting. 
source = plane_source(host_medium; direction = [1.0,0.0])

# region where the result will be plot
M=N=5.0;
bottomleft = [-M;-N]; topright = [M;N];
region = Box([bottomleft, topright]);

sim = FrequencySimulation(Resonator, source);
list_ω = [1.99,3.99,2.74]
result = run(sim, region, list_ω, basis_order=5,only_scattered_waves=true; res=200)


# generate the plots of the fields
# pyplot()
# pyplot(size = (300,300))
for p=1:3 # loop on the different frequencies
    plot(result,list_ω[p]; seriestype = :contour,c=:balance) # clim=(-5.0,5.0)
    colormap("RdBu")
    plot!(Resonator,colorbar=true,
       title="Field at ω="*string(list_ω[p]),axis=false, xguide ="",yguide ="")
    savefig("plot_"*string(p)*".png")
end