In firearms, rifling is machining helical grooves into the internal (bore) surface of a gun's barrel for the purpose of exerting torque and thus imparting a spin to a projectile around its longitudinal axis during shooting to stabilize the projectile longitudinally by conservation of angular momentum, improving its aerodynamic stability and accuracy over smoothbore designs.
Flow measurement is the quantification of bulk fluid movement. Flow can be measured using devices called flowmeters in various ways. The common types of flowmeters with industrial applications are listed below:
A nozzle is a device designed to control the direction or characteristics of a fluid flow as it exits an enclosed chamber or pipe.
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of a pipe. The Venturi effect is named after its discoverer, the 18th-century Italian physicist Giovanni Battista Venturi.
A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres.
Internal ballistics, a subfield of ballistics, is the study of the propulsion of a projectile.
An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow.
In fluid dynamics, drag is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers or between a fluid and a solid surface.
The study of fluid mechanics, a branch of physics that studies the movement of fluids and the forces that act upon them, dates back to pre-history. The Ancient Greeks developed many of the basics of the field, while most concepts and theories used in modern physics were discovered in 17th and 18th century Europe.
The Manning formula or Manning's equation is an empirical formula estimating the average velocity of a liquid flowing in a conduit that does not completely enclose the liquid, i.e., open channel flow. However, this equation is also used for calculation of flow variables in case of flow in partially full conduits, as they also possess a free surface like that of open channel flow. All flow in so-called open channels is driven by gravity.
Choked flow is a compressible flow effect. The parameter that becomes "choked" or "limited" is the fluid velocity.
Torricelli's law, also known as Torricelli's theorem, is a theorem in fluid dynamics relating the speed of fluid flowing from an orifice to the height of fluid above the opening. The law states that the speed v of efflux of a fluid through a sharp-edged hole at the bottom of the tank filled to a depth h is the same as the speed that a body would acquire in falling freely from a height h, i.e. , where g is the acceleration due to gravity. This expression comes from equating the kinetic energy gained, , with the potential energy lost, mgh, and solving for v. The law was discovered by the Italian scientist Evangelista Torricelli, in 1643. It was later shown to be a particular case of Bernoulli's principle.
An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel.
A muzzle-loading rifle is a muzzle-loaded small arm or artillery piece that has a rifled barrel rather than a smoothbore. The term "rifled muzzle loader" typically is used to describe a type of artillery piece, although it is technically accurate for small arms as well. A shoulder arm is typically just called a "rifle", as almost all small arms were rifled by the time breechloading became prevalent. Muzzle and breechloading artillery served together for several decades, making a clear distinction more important. In the case of artillery, the abbreviation "RML" is often prefixed to the guns designation; a Rifled breech loader would be "RBL", or often just "BL", since smoothbore breechloading artillery is almost nonexistent. A muzzle loading weapon is loaded through the muzzle, or front of the barrel. This is the opposite of a breech-loading weapon or rifled breechloader (RBL), which is loaded from the breech-end of the barrel. The rifling grooves cut on the inside of the barrel cause the projectile to spin rapidly in flight, giving it greater stability and hence range and accuracy than smoothbore guns. Hand held rifles were well-developed by the 1740s. A popularly recognizable form of the "muzzleloader" is the Kentucky Rifle, which was actually developed in Pennsylvania. The American Longrifle evolved from the German "Jäger" rifle.
Pressure drop is defined as the difference in total pressure between two points of a fluid carrying network. A pressure drop occurs when frictional forces, caused by the resistance to flow, act on a fluid as it flows through a conduit. This friction converts some of the fluid’s hydraulic energy to thermal energy. Since the thermal energy cannot be converted back to hydraulic energy, the fluid experiences a drop in pressure, as is required by conservation of energy.
The following are terms related to firearms and ammunition topics.
In fluid dynamics the Borda–Carnot equation is an empirical description of the mechanical energy losses of the fluid due to a (sudden) flow expansion. It describes how the total head reduces due to the losses. This is in contrast with Bernoulli's principle for dissipationless flow, where the total head is a constant along a streamline. The equation is named after Jean-Charles de Borda (1733–1799) and Lazare Carnot (1753–1823).
Flow conditioning ensures that the “real world” environment closely resembles the “laboratory” environment for proper performance of inferential flowmeters like orifice, turbine, coriolis, ultrasonic etc.
A whistle is a device that makes sound from air blown from one end forced through a small opening at the opposite end. The physical theory of the sound-making process is an example of the application of fluid dynamics or hydrodynamics and aerodynamics. By understanding how geometry, dimensions, and fluid properties can affect the whistle, one can predict its properties, such as the resulting sound. The principles relevant to whistle operation also have applications in other areas, such as fluid flow measurement.
A high pressure jet is a stream of pressurized fluid that is released from an environment at a significantly higher pressure than ambient pressure from a nozzle or orifice, due to operational or accidental release. In the field of safety engineering, the release of toxic and flammable gases has been the subject of many R&D studies because of the major risk that they pose to the health and safety of workers, equipment and environment. Intentional or accidental release may occur in an industrial settings like natural gas processing plants, oil refineries and hydrogen storage facilities.
