k-Wave User Forum » Topic: Unwanted Edge Waves in 3D simulation

k-Wave User Forum » Topic: Unwanted Edge Waves in 3D simulation http://www.k-wave.org/forum/topic/unwanted-edge-waves-in-3d-simulation Support for the k-Wave MATLAB toolbox en-US Fri, 05 Jun 2026 12:41:07 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php tripsi on "Unwanted Edge Waves in 3D simulation" http://www.k-wave.org/forum/topic/unwanted-edge-waves-in-3d-simulation#post-9250 Wed, 27 May 2026 12:16:07 +0000 tripsi 9250@http://www.k-wave.org/forum/ Hi, I am trying to run simulations to model the ultrasound propagation of a focused transducer in 3D. My issue is that my source creates non-physical edge waves at the edges of the source. (My source is modeled as a bowl.) The edge waves also appear in a linear simulation and in 2D simulations. However, in 2D simulations, the effect is much weaker. I don't believe that the problem is a discretization issue because I have not perceived any improvements when reducing the grid spacing. Is there a solution to this? I have also attached the code for more detailed information. Thank you! clearvars; % Clears all variables D = 64e-3; % Aperture diameter [m] C = 98e-3; % Radius of Curvature [m] c = 1482; % Speed of Sound [m/s] f = 1.1e6; % Frequency [Hz] mag = 3e5; % Magnitude [Pa] rho = 998.2; % Density [kg/m^3] cfl = 0.3; % Domain x_dim = 80e-3; % [m] y_dim = 160e-3; % [m] z_dim = 80e-3; % Size of the domain (grid points) Nx = 864; Ny = 2048; Nz = 864; % ========================================================================= % SIMULATION % ========================================================================= % create the computational grid dx = x_dim/Nx; % grid point spacing in the x direction [m] dy = y_dim/Ny; % grid point spacing in the y direction [m] dz = z_dim/Nz; % grid point spacing in the z direction [m] % Create the grid kgrid = kWaveGrid(Nx, dx, Ny, dy,Nz,dz); % define the properties of the propagation medium medium.sound_speed = c ; % [m/s] medium.density = rho ; % [kg/m^3] medium.alpha_coeff =2.17e-3; % [dB/(MHz^y cm)] for water medium.alpha_power = 2; %water medium.BonA = 5.0; % solve nonlinear equations distanceTraveledAtTEnd = 160e-3; tEnd = distanceTraveledAtTEnd/ min(medium.sound_speed(:)); kgrid.makeTime(medium.sound_speed,cfl,tEnd); grid_size = [Nx,Ny,Nz]; bowl_pos = [Nx/2,50,Nz/2]; % position of the center of the bowl%50 radius = round(C/dx); % in grid spaces diameter = 2*floor(D/(2*dx))+1; % in grid spaces focus_pos = [Nx/2,400,Nz/2]; % position of the focus bowl_1 = makeBowl(grid_size, bowl_pos, radius, diameter, focus_pos, 'Plot', false); source.p_mask = bowl_1; % define a time varying sinusoidal pressure burst source_freq = f; % [Hz] source_mag = mag; number_cycles = 4; sinePressure = source_mag * sin(2 * pi * source_freq * kgrid.t_array); % ensure smooth transition from mag=0 to mag=source_mag and the reverse % model one pressure burst via Tukey window burst_duration = number_cycles/source_freq; t_mask = kgrid.t_array(kgrid.t_array <= burst_duration); num_samples_in_burst = length(t_mask); window = [transpose(tukeywin(num_samples_in_burst, 0.5)), ... zeros(1, length(kgrid.t_array) - num_samples_in_burst)]; source.p = sinePressure .* window; % Apply the Tukey window to the pressure signal %filter the source to remove any high frequencies not supported by the grid source.p = filterTimeSeries(kgrid, medium, source.p); % create sensor - line along transducer axis % sensor.mask = [Nx/2, 70, Nz/2, Nx/2,1999,Nz/2].'; sensor.mask = zeros(Nx, Ny,Nz); sensor.mask(1:2:Nx, 1:2:799,1:2:Nz) = 1; sensor.record = {'p_final'};%, 'p_max', 'p_min'}; % run the simulation input_args = {'PMLSize', 30, 'PMLInside',true, 'SaveToDisk', 'input'}; sensor_data = kspaceFirstOrder3D(kgrid, medium, source, sensor, input_args{:});