PRE-LAB QUESTIONS

1. What is Bernoulli’ theorem?

Bernoulli theorem, in fluids dynamics, relation among the pressure, velocity, and elevation in a moving fluid (liquid or gas), the compressibility and viscocity (internal friction) of which are negligible and the flow of which is steady, or laminar. First derived (1738) by the swiss mathematician, Daniel Bernoulli, the theorem states, in effect, that the total mechanical energy of the flowing fluid, comprising the energy associated with fluid pressure, the gravitational potential energy of elevation, and the kinetic energy of fluid motion, remains constant. Bernoulli is theorem is the principles of energy conservation for ideal fluids in steady, or streamline, flow and is the basis for many engineering application. Bernoulli theorem implies, therefore, that if the fluid flows horizontally so that no change in gravitational potential energy occurs, then a decrease in fluid pressure is associated with an increase in fluid velocity. If the fluid is flowing through a horizontal pipe of varying cross-sectional area, for example, the fluid speeds up in constricted areas so that the pressure the fluid exerts is least where the cross section is smallest. This phenomenon is sometimes called the venturi effect, after the Italian scientist G.B. venturi (1746-1822), who first noted the effect of constricted channels on fluid flow.

2. Why the water levels in the various piezometric tubes are different? Another way to think of it is to take the rule the water wants to minimize its potential energy. The potential energy is just the average height of all the water, times its weight. If the water level were higher on the right, we could skim a little water off the top there and dump it on the left. The water we moved would go down some while the rest of the water would stay at the same height, so the average level would go down. Hence, it wasn’t at a minimum before. Only if the water level is the same everywhere is there no way to skim a little from one spot, dump it somewhere else, and reduce the potential energy.

3. State one practical application of Bernoulli’s theorem.

Bernoulli’s theorem says that the pressure of a fluid decreases as its speed increases. There are many practical applications that are in use every day. For example, an air planes relies on Bernoulli’s theorem to generate lift on its wings. The curve of the wing makes the air move faster, reducing its pressure. Another common application is the carburettor. The air moving through the throat “pulls” fuel into the air stream due to its reduced pressure.

Discussion In fluid dynamics, Bernoulli’s principle state that for an invalid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in the fluid’s potential energy.

Conclusion

From the result obtained, we can conclude that the Bernoulli’s equation is valid for flow as it obeys the equation. As the area decrease at a section (throat section) velocity increase and the pressure decrease. Besides, we know how to arrange work procedure accordingly and execute safety and health procedure. We also know about how to handle and given task correctly and how we identify the data needed. Lastly, we also can accomplish the task within a time frame given and to document the task and procedure the report.

Referens

1. Hydraulic guild laboratory lab report2. Textbook of hyraulic , written by En. Nizam Bin Jasmi , En. Mohd Ali Bin Jasmi ,

Pn. Sarah Afzan Binti Karim dan Pn. Hamidah Binti Zakaria . 3. Internet

- www.civilengineering .com