Extending the simulations</a></li>		
	</ul>
</div>

<a name="heading2"></a>
<h2>Simulation approach</h2>

<p>To minimise the computational overhead of running multiple 3D simulations with large grid sizes, the total number of elements in the ultrasound transducer is set to the number of active elements (in this case 32). This allows a smaller computational grid to be used. For each new scan line, the values for <code>medium.sound_speed</code> and <code>medium.density</code> within the computational grid are