Mach Number and Classify Fluid Flow Regimes Pressure and Thrust, Lift and Drag - Lab Report Example

Wind Tunnel Report Introduction Technological advancement has brought about the concept of understanding behaviours of text subjects without necessarily subjecting the real object to the conditions. One of the areas that the technology is employed is in aeronautics. Understanding the behaviour of an aeroplane subjected to varying wind and air condition is imperative before materializing a certain concept or making changes in an aeroplane. The quest to achieve efficiency and safety led to the development of the wind tunnel. A wind tunnel is a tool with a large tube where the effect of movement of air past objects can be tested. National Aeronautics and Space Administration (NASA) employs this technology with high precision so as to improve accuracy while constructing flying objects. Control is achieved due to the ability to control flow conditions thus able to subject the object to various aerodynamics forces. Mach number and classify fluid flow regimes Mach number is an important parameter in fluid flow. It is a dimensionless quantity that relates the speed of the fluid in a particular medium and the speed of sound propagated through the same media. In fluid dynamics, many fundamental equations and relations can be written in terms of Mach number. Mach number can be represented by the equation M=​Vs​/V​f​​​​ Whereby M is the Mach number, Vs the fluid velocity, and Vf is the velocity of sound in the same media (Lee 2012). A good understanding of the flow regime or rather geometric configuration of the fluid movement is imperative in the design and analysis of the fluid systems. Fluid flow can be broadly classified into two main categories namely the turbulent flow and the laminar flow. Turbulent flow refers to that type of flow whereby the motion is characterized by irregular flow paths that lead to mixing and variation of velocity of the fluid at different points. On the other hand, laminar flow refers to the type of flow characterized by the smooth movement along a defined path with the fluid layers in position thus minimal or no mixing of the fluid. A good understanding of the two broad classifications of the flow regimes is imperative for a strong foundation in understanding fluid flow dynamics (Yu and Hameiri 2013). Pressure and thrust, lift and drag Thrust and pressure are crucial parameters when it comes to fluid flow dynamics. Thrust refers to the force applied perpendicularly to a surface while pressure is the thrust on a surface per unit area. The two parameters can be measured using different equipment. The SI unit of thrust is Newton (N) while that of pressure is Newton per square meter (N/m2). Mathematically, pressure can be represented as: Pressure= Force (N)/ Area (m2) Drag and lift are two crucial components in the understanding and analysis of the aerodynamic force. The drag is that projection that is parallel to the relative wind motion. It is the force that goes against the motion of an airplane or rather opposes the motion of an airplane. It is a force that originates from contact between object body and the fluid which in case of an airplane is air. On the other hand, lift the component in aerodynamic force that projects onto the two possible directions that are perpendicular to the relative wind movement direction (Anderson and Eberhardt 2010). Bernoulli’s principle and its relevance for the theory of lift generation Bernoulli's principle forms the basis of the aviation industry or rather air transport. It is a principle developed by a scientist known as Daniel Bernoulli. It states that an increase in the velocity of a fluid is accompanied by a significant decrease in pressure of the fluid or rather reduction in the potential energy of the fluid. The principle provides guidance in the design of the shape of the wings of aircrafts which ensures that enough lift is provided. The design of wings of the aircraft is such that the speed of air on the top side is higher than on the lower side thus pressure on the lower side becomes more. The pressure variation between the lower and upper side of the wings of an aircraft provides the lift force. The faster an aircraft moves, the more the lift since velocity on the top side increases increasing the lift force on the downward side of the wing (Anderson 2009). Principle of velocity measurement by Pitot tube Pitot tube is a very vital instrument in the aviation industry. It is used to measure the flow velocity of fluids by using several principles and parameters. The instrument measures the velocity of the fluid passing through the pipe by recording the difference in fluid pressure between two points in the pipe. It is an instrument that uses the Bernoulli's principle and equations to determine the fluid velocity. Several parameters of the moving air are determined, and their relations used to indicate the fluid velocity. Static pressure is the first component, and it refers to the amount of fluid pressure exceeding the prevailing atmospheric pressure. The other component is the stagnation pressure that refers to the level at which the fluid pressure, inclusive of kinetic energy converted to pressure, exceeds the prevailing atmospheric pressure (Bengtson 2015). The third component is the dynamic pressure. It is the measurement of how much the stagnation pressure exceeds the static pressure at a particular point in a fluid. For determination of the velocity, there is an equation relating the variables which when rearranged can be used to determine the fluid velocity. Pstag = P + ½ ρV2 + γh Pstag is the stagnation pressure V represents the velocity of the fluid y represents the specific weight of the fluid Magnus effect Magnus effect refers to a scenario whereby a spinning ball moves away or deviates from its principal path. The effect is mostly applied in sports involving the use of ball such as soccer. It is based on Bernoulli's principle whereby the difference in air velocity of air between the two sides of a spinning ball brings about the deviation from the expected path of projection. It can also occur sideways all depending on the direction of spin of the ball or rather the spherical object. It is applied in other fields of production such as in ships. A spherical ball is installed in the lower part of the ship and its spin controlled provides either uplift or downward force. Also, some flying objects have been created using the Magnus effect whereby balls are installed in the front of the wings providing either uplift or downward force depending on the direction of spin. Conclusion In conclusion, fluid dynamics provides the basis for the creation of flying objects. It is imperative to understand in details the parameters involved for the generation of safe flying objects like aircrafts. Furthermore, the technology is not only used in the flying objects but also in the stability of supercars. The spoilers installed in the back of the care creates a downward force helps keep the car stable even when it is moving at high speeds. Further research in the field is crucial to determine better and more accurate methods of measurement of these parameters. References Anderson, B. (2009). The physics of sailing explained. Dobbs Ferry, NY: Sheridan House. Anderson, D. and Eberhardt, S. (2010). Understanding flight. New York: McGraw-Hill. Bengtson, H. (2015). Fluid Velocity Measurement Using a Pitot Tube (Pitot Static Tube). [online] Brighthub Engineering. Available at: http://www.brighthubengineering.com/hydraulics-civil-engineering/58382-how-to-measure-fluid-velocity-with-a-pitot-tube/ [Accessed 27 Apr. 2015]. Chebbi, B. and Tavoularis, S. (2009). Pitot–static tube response at very low Reynolds numbers. Physics of Fluids A: Fluid Dynamics, 3(3), p.481. Lee, S. (2012). Effects of condition number on preconditioning for low Mach number flows. Journal of Computational Physics, 231(10), pp.4001-4014. Scott, P. (2015). Bernoulli's Principle and Airplane Aerodynamics. [online] Physicsmyths.org.uk. Available at: http://www.physicsmyths.org.uk/bernoulli.htm [Accessed 27 Apr. 2015]. Yu, B. and Hameiri, E. (2013). Plasma flow at a high Mach-number. Physics of Plasmas, 20(9), p.092507. Zhu, Y., Wang, Y. and Wang, X. (2012). Numerical Simulation of the Effect of Section Size on Averaging Pitot Tube. AMM, 188, pp.277-282. Read More