Ultrasound Refraction

• Big surface: Ultrasound refraction only happen at big surface compared to its wavelength.
• Velocity mismatch: The acoustic medium at both sides of the surface must have different sound velocity.
• Dependence on angle: The refracted wave obey Snell's Law.
• Plane wave refracted by acoustic medium with faster sound velocity
  
• Plane wave refracted by acoustic medium with slower sound velocity
  
• Spherical wave refracted by acoustic medium with faster sound velocity
  
• Spherical wave refracted by acoustic medium with slower sound velocity