wave machine 
noun
A machine that creates waves in the water in a swimming pool.He has recently been consulted on an embryonic project to put a wave machine into a water park in Strathclyde Park....
- The mansion, with a white-sand swimming pool and wave machine, is named after the famous central Philippine beach resort called in many travel books ‘the best beach in the world’ for its 4-kilometer stretch of powdery white sand.
- The devastating tsunami was a direct consequence of the earthquake, which caused movement of the seafloor all along the length of the rupture, like a huge wave machine.