Compressor surge is a form of aerodynamic instability in axial compressors or centrifugal compressors. The main part of a centrifugal compressor is the impeller. Mixed-flow waterjet designs incorporate aspects of both axial flow and centrifugal flow pumps. Magnetic bearing (magnetically levitated) and air bearing centrifugal compressors exist. The speed lines of gas turbine centrifugal compressors typically exhibit choke. There are three basic types of pumps&colon; positive displacement, centrifugal and axial-flow pumps. Overspeed governors are either centrifugal or hydraulic. The parallel turbine is similar to the crossflow fan or centrifugal fan. The inlet to a centrifugal compressor is typically a simple pipe. Hence, it experiences equal and opposite centripetal & centrifugal forces. The engine was cooled by a centrifugal pump. It is defined by centrifugal and axial pumps' inherent physical characteristics and operating point. Further, testing centrifugal compressor performance is very complex. The construction is based on hybrid concept of centrifugal pump and turbopump. I have characterized the social struggle as centrifugal and social solidarity as centripetal.