Examples of fluid in the following topics:
-
- Flow velocity and volumetric flow rates are important quantities in fluid dynamics used to quantify motion of a fluid and are interrelated.
- Fluid dynamics is the study of fluids in motion and corresponding phenomena.
- Fluid velocity can be affected by the pressure of the fluid, the viscosity of the fluid, and the cross-sectional area of the container in which the fluid is travelling.
- The magnitude of the fluid flow velocity is the fluid flow speed.
- Fluid flow velocity effectively describes everything about the motion of a fluid.
-
- Virtually all moving fluids exhibit viscosity, which is a measure of the resistance of a fluid to flow.
- It describes a fluid's internal resistance to movement and can be thought of as a measure of fluid friction.
- The greater the viscosity, the ‘thicker' the fluid and the more the fluid will resist movement.
- Different fluids exhibit different viscous behavior yet, in this analysis, only Newtonian fluids (fluids with constant velocity independent of applied shear stress) will be considered.
- In analyzing the properties of moving fluids, it is necessary to determine the nature of flow of the fluid.
-
- A fluid is a substance that continually deforms (flows) under an applied shear stress.
- A fluid is a substance that continually deforms (flows) under an applied shear stress.
- The distinction between solids and fluid is not entirely obvious.
- It is best described as a viscoelastic fluid.
- This also means that all fluids have the property of fluidity.
-
- The flow rate of a fluid is the volume of fluid which passes through a surface in a given unit of time .
- where Q is the flow rate, v is the velocity of the fluid, and a is the area of the cross section of the space the fluid is moving through.
- The equation of continuity applies to any incompressible fluid.
- Since the fluid cannot be compressed, the amount of fluid which flows into a surface must equal the amount flowing out of the surface.
- Using the known properties of a fluid in one condition, we can use the continuity equation to solve for the properties of the same fluid under other conditions.
-
- For a fluid at rest, the conditions for static equilibrium must be met at any point within the fluid medium.
- Thus for any region within a fluid, in order to achieve static equilibrium, the pressure from the fluid below the region must be greater than the pressure from the fluid above by the weight of the region.
- At the same time, there is an upwards force exerted by the pressure from the fluid below the object, which includes the buoyant force. shows how the calculation of the forces acting on a stationary object within a static fluid would change from those presented in if an object having a density ρS different from that of the fluid medium is surrounded by the fluid.
- The appearance of a buoyant force in static fluids is due to the fact that pressure within the fluid changes as depth changes.
- This figure is a free body diagram of a region within a static fluid.
-
- Bernoulli's equation states that for an incompressible and inviscid fluid, the total mechanical energy of the fluid is constant .
- (An inviscid fluid is assumed to be an ideal fluid with no viscosity. )
- The kinetic energy of the fluid is stored in static pressure, $p_s$, and dynamic pressure, $\frac{1}{2}\rho V^2$, where \rho is the fluid density in (SI unit: kg/m3) and V is the fluid velocity (SI unit: m/s).
- Static pressure is simply the pressure at a given point in the fluid, dynamic pressure is the kinetic energy per unit volume of a fluid particle.
- Syphoning fluid between two reservoirs.
-
- Torricelli's law is theorem about the relation between the exit velocity of a fluid from a hole in a reservoir to the height of fluid above the hole.
- Torricelli's law is theorem in fluid dynamics about the relation between the exit velocity of a fluid from a sharp-edged hole in a reservoir to the height of the fluid above that exit hole .
- This relationship applies for an "ideal" fluid (inviscid and incompressible) and results from an exchange of potential energy,
- Due to the assumption of an ideal fluid, all forces acting on the fluid are conservative and thus there is an exchange between potential and kinetic energy.
- The exit velocity depends on the height of the fluid above the exit hole.
-
- For an ideal fluid we found that the stress tensor took a particular form,
- where $w=(\epsilon + P)/\rho$ is the heat function (enthalpy) per unit mass of the fluid.
- In the ideal fluid, no heat is transferred between different parts of the fluid, so if we denote $s$ as the entropy per unit rest mass we have
- for a bunch of fluid; therefore, we also have a continuity equation for the entropy
-
- Pascal's Principle states that pressure is transmitted and undiminished in a closed static fluid.
- Pascal's Principle (or Pascal's Law) applies to static fluids and takes advantage of the height dependency of pressure in static fluids.
- As stated by Pascal's Principle, the pressure applied to a static fluid in a closed container is transmitted throughout the entire fluid.
- In the second configuration, the geometry of the system is the same, except that the height of the fluid on the output end is a height Δh less than the height of the fluid at the input end.
- The difference in height of the fluid between the input and the output ends contributes to the total force exerted by the fluid.
-
- Objects moving in a viscous fluid feel a resistive force proportional to the viscosity of the fluid.
- A moving object in a viscous fluid is equivalent to a stationary object in a flowing fluid stream.
- We use another form of the Reynolds number N′R, defined for an object moving in a fluid to be
- where L is a characteristic length of the object (a sphere's diameter, for example), the fluid density, its viscosity, and v the object's speed in the fluid.
- (a) Motion of this sphere to the right is equivalent to fluid flow to the left.