21. In 1726, Euler equations which could be applied to both compressible and incompressible flows. 22. When the density is allowed to vary, the problem is called a compressible problem. 23. They may also be used to transfer building loads past weak or compressible soil layers. 24. In a subsonic flow the gas is compressible , and sound will propagate through it. 25. Crash safety improved with this change because of a compressible structure behind the front bumper. 26. :Most buoyant materials are relatively compressible . 27. As air is compressible , this might not add much resistance but it might help. 28. Specifically, this applies to signals that are sparse ( or compressible ) in some domain. 29. Compressible flow is responsible for these changes in pressure, velocity, density, and temperature.30. Liquids are only very slightly compressible .
