The Founder of Modern Fluid Dynamics: Ludwig Prantdl

Drag is a mechanical force, It is generated by the interaction and contact of a solid body with a fluid (liquid or gas).For drag to be created, the solid body must be in contact with the fluid. If there is no fluid, there is no drag. Drag is generated by the difference in velocity

Liquid: having a consistency like that of water or oil, flowing freely but of a constant volume.

A Newtonian fluid is a fluid that exhibits constant viscosity regardless of any external stress applied to it, like mixing or a sudden application of force. Like water; this flows in the same direction regardless of whether it’s left alone or agitated. A Newtonian fluid, by definition, can only be affected by pressure and temperature together, or temperature, but not pressure on its own.

The boundary layer can also be measured by other factors. One factor is the Displacement Thickness, δ*. It is defined as the distance by which the free streamlines are displaced in the y-direction due to the formation of the boundary layer. The formation of the boundary layer reduces the mass flow rate per unit area. This is because near the surface the molecules are travelling slower, meaning less flow rate per unit area is going out compared to coming in. In order to compensate for this loss in mass flow rate, the external streamlines (free streamlines) will be displaced. The distance it displaced is the δ*. [5] When deriving this equation it is assumed the flow is incompressible and steady.

Liquid has a physical property called viscosity, which tells how fast or slow it flows. The more viscous a substance is, the slower

In water, an object has to be less dense than water to float. The same goes for cereal, which is less dense than milk and allows them to float. In liquids, cohesive forces are strong enough to keep molecules together but weak enough to slide past each other. Fluids with high viscosity have strong cohesive forces and fluids with low cohesive forces have weak cohesive forces. Viscosity can be calculated by its flow rate.

side-stream B exists, where additional air flows into pipe. At first, molecules of influx B just ´stand´ locally and represent no stronger resistance than main-stream is affected by friction on inner faces of pipe. Particles of that ´resting´ air at B are trembling, based at normal molecular movements, thus are flying into all directions from one collision to next. Just by pure chance, any particle will be pushed into direction of main-stream. That particle moves ahead within main-stream, and will not come back to influx-area.

He is the earliest writer who attempted to formulate a kinetic theory of gases, and he applied the idea to explain Boyle's law.[2]

All the essays talk about matter. A matter is a solid, liquid, gas, plasma. But we do not focus on the state of matter plasma. We don't do this because it is simpler to say three states of matter.

Before we conduct the experiment, we must first understand what viscosity is. “Viscosity is the quantity that describes a fluid's resistance to flow”.1 It is essentially fluid friction and transforms kinetic energy of motion into heat energy, just as friction (“the force between surfaces in contact that resists their relative tangential motion”) does between

Alternatively, it can also be explained by referring to the equation , where the k value is constant while the hydraulic gradient i defined by i = ΔH/L increases because the head difference ΔH is constant while the flow length L becomes shorter when it gets closer to the barrier wall.

The volume is definite if the temperature and pressure are constant. When a solid is heated above its melting point, it becomes liquid, given that the pressure is higher than the triple point of the substance. Intermolecular (or interatomic or interionic) forces are still important, but the molecules have enough energy to move relative to each other and the structure is mobile. This means that the shape of a liquid is not definite but is determined by its container. The volume is usually greater than that of the corresponding solid, the most well known exception being water, H2O. The highest temperature at which a given liquid can exist is its critical temperature.[5]

     Drag force is the cost of increasing downforce. Drag force is the force acting on an object in motion in the opposite direction the object is moving through a fluid (Yager). To most people drag force is simply known as air resistance. The objective of aerodynamic efficiency is to maximize downforce while minimizing drag force.

[2] Kinnas, Dynamic Viscosity of Air as a Function of Time, http://www.ce.utexas.edu/prof/kinnas/319lab/Book/CH1/PROPS/GIFS/dynair.gif Accessed on 15/04/2013

The lid-driven cavity flow is most probably one of the most studied fluid problems in the