README.md

Simple random particles example

## Define particle properties
Define the volume fraction of particles, the region to place the particles, and their radius
```julia
using MultipleScattering
num_particles = 4
radius = 1.0

particle_medium = Acoustic(2; ρ=0.2, c=0.1) # 2D particle with density ρ = 0.2 and soundspeed c = 0.1
particle_shape = Circle(radius)

max_width = 20*radius
bottomleft = [0.,-max_width]
topright = [max_width,max_width]
region_shape = Box([bottomleft,topright])

particles = random_particles(particle_medium, particle_shape; region_shape = region_shape, num_particles = num_particles)

Now choose the receiver position x, the host medium, set plane wave as a source wave, and choose the angular frequency range ωs

x = [-10.,0.]
host_medium = Acoustic(2; ρ=1.0, c=1.0)
source =  plane_source(host_medium; position = x, direction = [1.0,0.])

ωs = LinRange(0.01,1.0,100)

simulation = FrequencySimulation(particles, source)
result = run(simulation, x, ωs)

We use the Plots package to plot both the response at the listener position x

    using Plots; #pyplot(linewidth = 2.0)
    plot(result, field_apply=real) # plot result
    plot!(result, field_apply=imag)
    #savefig("plot_result.png")

And plot the whole field inside the region_shape bounds for a specific wavenumber (ω=0.8)

    bottomleft = [-15.,-max_width]
    topright = [max_width,max_width]
    bounds = Box([bottomleft,topright])

    #plot(simulation,0.8; res=80, bounds=bounds)
    #plot!(region_shape, linecolor=:red)
    #plot!(simulation)
    #scatter!([x[1]],[x[2]], lab="receiver")

    #savefig("plot_field.png")

Things to try

• Try changing the volume fraction, particle radius and ω values we evaluate