Turbines are machines that convert rotational energy generated by sources such as water, steam, fluids, air and gases into usable energy forms such as electricity, mechanical work, propulsion, thrust, and much more. The basic structure of a turbine consists of a rotating shaft or drum, and attached blades.

Types of turbines
Following are the most common types of turbines.

Shrouded turbine
Many turbines have shrouded interlocked blades to enhance damping and thereby reduce blade flutter. In large and low pressure steam turbines, the blades are lace wired at the center to further minimize flutter and lower the risk of blade failure.

Shroudless turbine
Contemporary turbine blades are not shrouded to reduce the centrifugal load and increase the efficiency of the turbine while reducing any cooling requirement.

Steam turbine
Steam turbines are commonly used in thermal power plants to generate electricity using coal, fuel oil or nuclear power as the energy source.

Gas turbine or turbine engine
A gas turbine generates propulsion. It is composed of one or more turbines, typically combined with an inlet, fan, compressor, ducts, heat exchanger, nozzle, combustor and an alternator if used to produce electricity. 

Transonic turbine
The gas flow in transonic turbines reaches supersonic speeds when it comes out of the nozzle guide vanes, reducing to subsonic as it travels downstream. These turbines work at high pressure ratios but have low efficiency.

Contra-rotating turbine
A rotating unit at one end increases the efficiency of the contra-rotating turbine by coupling with a unit on the other end rotating in the opposite direction. Multi-stage radial turbines are used to generate electricity in marine applications, where their less weight and compactness are an advantage.

Statorless turbine
In statorless turbines, gas flow exiting from an upstream rotor in a multi-stage turbine strikes a downstream rotor directly without the need for intermediate stator vanes that can change the pressure and velocity levels of the gas flow.

Ceramic turbine
Turbines conventionally have nickel alloy based blades that can withstand high pressure. A cooling mechanism prevents the metal from overheating. Ceramic blades do away with this need as they can withstand higher temperatures. However, their brittleness can lead to disastrous breakage of blades.

Water turbine
A water turbine uses the force of water to generate usable energy such as electricity. Variations are the Pelton turbine, Francis turbine, Kaplan turbine and Voith.

Wind turbine
A wind turbine converts the kinetic energy of the wind into mechanical or electrical energy. Usually wind turbines are single stage ensembles that do not use guide vanes or nozzles.

Tide turbine
Tidal power is harnessed by tide turbines to generate power.

Velocity compound "Curtis"
This turbine engine is popular in ships as it can be operated at different speeds, low pressure and low speeds.

Pressure Compound Multistage Impulse or Rateau
This turbine engine uses impulse motors separated by a nozzle diaphragm.

Bladeless turbine or cohesion–type turbine or Prandtl layer turbine
Unlike traditional turbines, this turbine works on the boundary layer effect. The Tesla turbine is a bladeless turbine.

Turbines are used in multiple industrial processes individually or as part of larger engines. They come in various sizes and even the smallest turbine has the potential to move heavy objects.