Method and apparatus for remotely changing flow profile in conduit and drilling bit

The present invention relates to apparatus and methods for remotely adjusting the drill bit hydraulic horse power per square inch (HSI). Varying the nozzle geometry remotely without the need to pull the drill string outside the hole has obvious advantage. Changing the nozzle flow geometry results in changing the nozzle HSI, which is beneficial to optimize drilling different rock formations in different drilling environment. There are many concepts to vary the nozzle size while drilling. The drill bit nozzle geometry can be varied by causing a change of at least one physical property of the environment. The variable geometry nozzle is not limited to drill bit, it can be placed within the inner flow passage or between the inner flow passage and annular flow passage for controlling flow profile within a wellbore, a tubular string or a flow conduit.