Monday, January 27, 2020

Pressure Distribution of Cylinder in Wind Tunnel

Pressure Distribution of Cylinder in Wind Tunnel This lab delved into the concepts of fluid mechanics to calculate the drag coefficient of airflow around a smooth cylinder resulting from variations in pressure distribution. An apparatus consisting of a wind tunnel, pitot-tube, rotatable cylinder, and well-inclined manometer were used to conduct the experiment. Airflow generated by the wind tunnel was the driving factor, causing a measurable pressure difference around the cylinder. The well-inclined manometer was used to measure this varying pressure at ten degree intervals around the rotating cylinder, while the pitot-tube was utilized to measure free-stream velocity. After measuring and recording the necessary data for three different air speeds, calculations were made to determine Reynolds Number (Re), coefficient of pressure (Cp), and coefficient of drag (Cd). The resulting plots of Cp vs. Theta (angle of pressure measurement around cylinder) were consistent with the shape of the graph for laminar flow found within the text, ind icating separation at about 75-80 degrees. The plot of Cd vs. Re was also successful considering our Cd showed a small increase and a slight decrease over the range of Reynolds values (remaining more or less constant). This result is consistent with the figure provided from the Fluid Mechanics text, as it is clear that Cd remains relatively steady for a smooth circular cylinder for the range 1000 Objective: The objective of this lab was: 1. To measure the pressure distribution around a circular cylinder placed in a rectangular crossà ¢Ã¢â€š ¬Ã‚ section wind tunnel, and to calculate the drag force based on the pressure measurements. 2. To Compare the measured pressure and drag force with the values calculated using the potential flow theory. Introduction: Because fluid matter is so abundant and plays such a significant role in science, fluid mechanics is a large area of study for scientists and engineers. One aspect of particular interest is in studying how fluids flow over different objects. Understanding this concept is crucial to solving problems that impact the modern world, such as atmospheric flight and automobile design (to name a few). By using a wind-tunnel, a smooth cylinder, and a few measuring devices to aid us, we were able to formulate a basis of experimental knowledge with which to observe fluid flow over an object made relatable by the parameters of pressure, drag, and Reynolds Number. Differing flow speeds allowed us further opportunity to compare and contrast the observations and calculations made relating to these parameters. In order to fully accomplish the objectives of this lab and report, background and theory concerning fluid mechanics must first be introduced to provide core, foundational knowledge. This knowledge is expanded upon by dictating the necessary equipment requirements to conduct the lab. From there, the experimental procedure is outlined to allow for reproducibility of the lab by the reader should the need arise. Finally, an analytical approach is used to examine the overall results of the lab as performed before generating several conclusions and recommendations for the future. Background Theory: The background of the experiment is to calculate the drag coefficient in a controlled environment using a wind tunnel, a rotating cylindrical object, pitot tube, and an inclined manometer. When developing the drag coefficient values it is important to specify the reference area (cylindrical object) used to develop the drag coefficient value. This value is valuable to engineers in developing models for many different aspects, such as, cars, airplanes, and many other areas as fluids affects just about everything. Fluid consists of air, water, gas which are Newtonian Fluids and in this experiment air was used to understand the effects experimentally with a rotating cylindrical object and checking the values on a manometer at 10 degree intervals at 3 different speeds low, medium, and high. Figure 1 Airflow around Cylindrical Object (3) Theory: The pitot tube at the point that is hit in the central part has a velocity of zero (see figure 2 below) and point2 is known as stagnation point. From the Bernoulli equation this point can be calculated per [(p1/à ¢Ã¢â‚¬Å¾Ã‹Å")+(u1^2/2)=(p2/à ¢Ã¢â‚¬Å¾Ã‹Å")], which can be re-written as p2 = p1+(.5*à ¢Ã¢â‚¬Å¾Ã‹Å"*u1^2). U1 = velocity, p1 p2 = pressure, à ¢Ã¢â‚¬Å¾Ã‹Å" = density and for stagnation at point 2, u2 = 0 and z1 = z2. (3) Figure 2 Pitot Tube Point 1 2 (3) When using a pitot static tube also known as Prandtl tubes (see figure 3), which is used to measure the pressure difference. The tube is mounted in the wind tunnel so that the main hole along the axis direction through the tube is pointed in the direction of the fluid flow and other small holes are drilled on the outside of the tube perpendicular to main hole and kept separately. The small perpendicular holes are considered the static pressure and the main hole is the total pressure (pressure of flow static) used in the Bernoulli equation. Figure 3 Pitot Static Tube (3) The manometer are used to measure the pressure and is one of the oldest measurement devices. There are different types of manometers that can be used, such as, the U-tube, Inclined, Reservoir, and Float types. For this experiment an inclined manometer is used so that the pressure changes can be read easier and has an increased sensitivity level compared to the others. (Equations for the Manometer) (3) (Note The scale of the installed manometer in this setup reads h directly, so you do not need to multiply it by sin ÃŽÂ ¸) Figure 4 Typical Inclined Manometer (3) Drag force on a circular cylinder in a stream of flow per Figure 5, 6, 7 below shows that the flow past a cylinder will go through several transitions based on the velocity. In this experiment as the cylindrical object rotates the fluid flow changes within the same velocity and delivers different values and is repeated between 3 different velocities and then compared. Figure 5 Separation of air flow around cylindrical object (3) Figure 6 Typical graph for separation of airflow (3) (a) Laminar Flow separates at about 80 °, CD = 0.5 (b) Turbulent flow separates at 120 °, CD = 0.2 Figure 7 Graph of separation of airflow around an object (3) (a) Laminar Flow separates at about 80 °, CD = 0.5 (b) Turbulent flow separates at 120 °, CD = 0.2 Equipment: The equipment used for this experiment were: 1. A rectangular crossà ¢Ã¢â€š ¬Ã‚ section wind tunnel. 2. An adjustable air blower responsible of pumping the air throughout the wind tunnel. 3. A rotatable circular cylinder placed across the whole height of the tunnel. 4. A pitotà ¢Ã¢â€š ¬Ã‚ tube to allow measurement of free stream air velocity. 5. A honeyà ¢Ã¢â€š ¬Ã‚ section to achieve a uniform flow across the tunnel. 6. A wellà ¢Ã¢â€š ¬Ã‚ inclined manometer to measure pressure around the cylinder. Procedure: Starting the experiment after reading the parameters of and required steps in the experiment we had to set a baseline for a further measurement in this experiment. This was done by taking readings for the inclined manometer, href used it this experiment with no added flow from the fan at ambient pressure. All measurements were recorded by two measurement takers and only dispute on a measurement was decided by a third party. Next the blower was turned on to slowest of the the three speeds to be used and reading was allowed some time to stabilize. The valve lever was then rotated to the horizontal position to record the manometer reading for the pitot tube which was lowered to be the same height as the hole in the cylinder. A manometer measurement was recorded for the pitot tube at this position. Following this, the valve handle was rotated to the vertical position and the pitot tube returned to its original position at the top of the apparatus in order to read the pressure around the cylinder. The cylinder was rotated to the zero degree position and that reading should, in principle, be the same as huà ¢Ã‹â€ Ã… ¾. The next stage of the experiment was to rotate the cylinder to the 10 degree position, re-read the manometer and record that value. The Άh now represented (href h), where h was the current reading on the manometer from the pressure probe connected to the hole in the cylinder. This process was repeated for the -10 degree position and then for the positive 20 degree, -20 degree position and so on for the rest of the experiment increasing by 10 degrees and the same increase for the negative direction. All of the data collected was put in an excel spreadsheet for every 10 degrees around the cylinder and its corresponding negative value as well. for the next part of the experiment we completed these same steps for the other two required blower speeds of medium and high with all the data logged in another book of the same spreadsheet Data Sheet: Results and Analysis: Because this lab was aimed to determine the drag force by measuring the pressure distribution and compare them to the actual results, we found that the drag forces are generated by the aero-dynamical resistance. Measurements of static pressure coefficient on the cylinder surface were used to determine the drag coefficient by adjusting the wind speeds at low, medium and high velocities and recording the respective values. Our experimental data was set to observe, collect data and analyze the accuracy of the appearing drag forces, FD the drag, CD and pressure, Cp coefficients at various pressure distributions of different angles and the Reynolds Numbers, Re. Results are presented in figures 10, 11 12 Figure 10: Drag force for 1.673 in. diameter of cylinder This figure above gives us an understanding of the relationship between the drag force and the wind speeds at various velocities. We can assume from the graph that the drag force becomes greater by increasing wind speeds. Figure 11: Drag coefficient at different Reynolds Number The figure shows surface pressure coefficient distributions at three Reynolds numbers compared with a theoretical distribution on the left computed assuming unbounded potential flow. If you observe the theoretical distribution on smooth circular cylinder, it shows us that the curve is exponentially decreasing as it comes to an equilibrium state within the Reynolds numbers range. But calculated distribution has a slight linear increase in the pressure coefficient and the Reynold numbers increase. The unexpected form of the pressure distribution on the cylinder may be partly explained by three dimensionality in the flow. The big difference between the measured and the theoretical value cannot be explained, but it was found, that the inlet velocity in front of the cylinder has a strong influence on the determined drag coefficient. Maybe a velocity measurement with a pitot tube in front of the cylinder would bring better results for the drag coefficient. Figure 12: Pressure coefficient of different angels The above graphs show a theoretical figure on the left and an experimented figure on the right. In the experiment we recorded the static and surface pressures of a cylinder having a diameter of 1.673 in and 6 in long. We rotated a built in protractor in 10 degree interval for readings over 00 to  ±1800. The experimental data of pressure coefficient, Cp obtained under the various angels of incidence for different conditions of low, medium and high velocities. We can observe from the two graphs that the curves are similar in shape. However, the high and medium curves turned out to be slightly similar. The slight error is quite visible comparing the two graphs but this can be caused due to various experimental situations. The pressure and velocity measurements with the pitot tubes are influenced by a chain of errors. Most of the measurement set-ups are linked: sensors, transducers and data acquisition systems. Each part of the system is influencing the measurements and adds a dev iation. The signal chain is going through a lot of steps for the Pitot tube: It starts with the Pitot tube themselves, which e.g. influences the flow. The pressure is transduced to an analogue electrical signal, which is conducted and transformed to a digital signal in the data acquisition system. These signals are set into account with the alcohol manometer data. The manometer is subjected to reading, adjustment and surface tension of liquids deviation. In the following a deviation estimation is done for the manometer. Pitot tubes are in general suitable to measure turbulent flows, but the output can be wrong or different, if the flow is highly turbulent and contains back flows. Also flows that hit the Pitot tube from the side or in big angles can induce lower measured velocities.From the appropriate formulas for calculating and plotting the coefficient of pressure Cp to determine the drag coefficient, Cd the above graphs shows us that: At elevated speeds the anticipated amount of lift and speed must be lower. Greater wind speed resulted in a larger speed coefficient The pressure on the circular cylinder seems to be higher at increased wind speeds from low to medium to high. We could presumably say that this is consistent with the theoretical aspect of flight control and aerodynamics. Note: The estimations of the quantities in dependency of the wind velocity, drag force and Reynolds Numbers are found on the attached excel file data sheets. Conclusion and Recommendations: This lab was successful in introducing and utilizing a variety of statistical concepts and their uses in describing data. Using the statistical analysis tools shown in this experiment were very helpful in organizing the data, identifying any outliers, being able to show trends and compare them. Understanding of key concepts such as drag and how it affects any design or system is very important. The two key components of the momentum suffered by the fluid, air, is this system are skin friction and form drag. Both of these interrupt the ideal laminar of the fluid. At the front of the cylinder the pressure is about equal to the stagnation pressure and, from there, start to accelerate further around the curved surface the readings are taken. This acceleration causes a drop in pressure relative to the position on the cylinder. These readings do accelerate until about 90/ 270 degrees from 0/180 degrees then the pressure slowly if not exactly linearly until it then levels off as the flow be comes more turbulent. All of the data that we collected in this experiment seems to support this conclusion at each of the three measured speeds.

Saturday, January 18, 2020

Cisco Feasibility Study

Computer shop business is the one of the most demand business here in the Stop. Ion Patters Tagging City, internet cafe's are really in demand because of the fast changing technology that the people embarrassed Just like here in the Philippines. Some have their own laptops and bring it to the malls so they could relax and at the same time prepare their assignments and paper works.The people today are very ND would want to do their Jobs in the beautiful innovative environment that could satisfy their needs and lessen their stress due to busy schedule OBJECTIVES/GOAL -To earn profit. -To satisfy costumers providing best quality services at effective price. -Providing the services at low cost by providing the best quality at affordable price. -To achieve its return of investment and the business giving satisfaction to the owner. VI'. Technical Feasibility vii-l Location b. Floor Plan Star network Star networks are one of the most common computer network topologies.In its implies form, a star network consists of one central switch, hub or computer, which act as a conduit to transmit messages. This consists of a central node, to which all other nodes are connected; this central node provides a common connection point for all nodes through a hub. In star topology, every node (computer workstation or any other peripheral) is connected to a central node called a hub or switch. The switch is the server and the peripherals are the clients Thus, the hub and leaf nodes, and the transmission lines between them, form a graph with the topology of a star.If the central node is passive, the originating node must be able to tolerate the reception of an echo of its own transmission, delayed by the two-way transmission time (I. E. To and from the central node) plus any delay generated in the central node. An active star network has an active central node that usually has the means to prevent echo-related problems. Advantages Better performance: star topology prevents the passing o f data packets through an excessive number of nodes.At most, 3 devices and 2 links are involved in any communication between any two devices. Although this topology places a huge overhead on the central hub, with adequate capacity, the hub very high utilization by one device without affecting others. Isolation of devices: Each device is inherently isolated by the link that connects it to the hub. This makes the isolation of individual devices straightforward and amounts to disconnecting each device from the others. This isolation also prevents any non- centralized failure from affecting the network.Benefits from centralization: As the central hub is the bottleneck, increasing its opacity, or connecting additional devices to it, increases the size of the network very easily. Centralization also allows the inspection of traffic through the network. This facilitates analysis of the traffic and detection of suspicious behavior. Easy to detect faults and to remove parts. No disruptions t o the network when connecting or removing devices. Installation and configuration is easy since every one device only requires a link and one input/output port to connect it to any other device(s).Disadvantages Failure of the central hub renders the network inoperable Communication between nodes must pass through the central hub. Therefore if the central hub is compromised, so is all communication. The hub is the bottleneck for throughput as it is required to retransmit the sum of all transmitted messages from devices.

Friday, January 10, 2020

Poy Sang Long

Poy Sang Long is a rite of passage practiced in Thailand and Myanmar. It`s three days and it involves kids age 7 to 14 dressed like Buddha’s son. The children ride on an adults back for two days and on the third day they go to a monastery where they have to live for at least a week or more. I think this is a great custom for all these children because they have fun participating in the festival for two days and after that they decide if they want to stay in the monastery for more the a week so it’s their decision if they want to become monks. I also think that the custom show grown in these kids because their knowledge increases and they come back from the monastery as new people who know more about their own religion . I would definitely do this rite of passage because it would give me a clear understating of how Buddhist live and I will learn martial arts along the way. If I really had a chance to do it I would be excited and interested in changing up my daily routine. The only thing that would give me trouble would be the 6 hours of meditating daily. I think the true purpose of this rite is to show uniqueness in Buddhism because I have never even heard of any right of passage close to that one. One of the main purposes is also to respect Buddha who stated that this will be a rite of passage for all the young children. The benefits of this right of passage are that people will gather to a commune event, kids will have fun and they will learn about their religion and they will experience what is like to live with monks. I also think that this right of passage can be harmful because of the discrimination against women. In a way it’s great that children learn so many new things but it’s only for boys so the girls are not allowed. And if I was a girl and I see my male friend and my brother let’s say for example I would ask myself why. Why am I different, why can’t I have fun like them and why can’t a become a monk. All this thoughts will stay in the girls mind and later on affect her by maybe lowering her self esteem and changing her beliefs about males. The three stage process about right of passage is to change from what you are to something new, to remove yourself from the society temporarily and to be re-admitted as a new person in the society. In Poy Sang Long the children change from being goofs to being smaller goofs in way because they learn about Zen meditation and they learn to control their emotions better. They are removed from the society by going to a monastery for a period of time and they are re-admitted back after the period is done. I think that this rite of passage follows the threes stage process but it varies because some of the children may become real monks.

Thursday, January 2, 2020

The Effects Of Advertising On Teens On The World Today

Communication Complications in Advertisements Teenagers views on the world today Advertisements surround us, and everyday they affect the unknowing minds of the younger generations. Researches have been investigating this topic for years, as the strategies these advertisements use are incredibly effective. This is shown through Pechmann Reibling (2006), Godbold Pfau (2000), Belstock, Connolly, Carpenter, Tucker (2008), Targeting teens. (1998) and What is the impact of advertising on teens? (n.d.). The research from these studies is extensive due to the long history of the influence of advertisements. Companies use advertisements to persuade and affect young persons worldviews and health behaviors. What is the impact of advertising on†¦show more content†¦That is a ploy to get more teenagers to buy from them, basically making teenagers vessels for sales. Parents do not realize how much this affects themselves, without even knowing it parents are also being blindsided to the fact that their child is losing his/her identity to the marketing industry. God bold (2000) discusses the use of advertisements affecting adolescents health. Godbold (2000) stated that underage drinkers who saw an informative or information-based anti-drinking public service announcement were less likely to adhere peer pressure. â€Å"The average age of initiation of alcohol use for adolescents is between 13 and 14† (p. 411 412). That is how quickly children can be influenced, at such an early age those children are already exposed to so much and letting these advertisements influence them can lead to a harmful future, or no future at all. As those adolescents go their use of alcohol tends to increase and a variation of things could possibly happen to them. Alcohol-related highway accidents, violent crimes, truancy, low performance in school, and even dropping out of school, and lifelong alcohol abuse behaviors are all potential consequences of the introduction of alcohol at such a young age. Belstock et al (2008) and Pechmann (2006) show how marketers use ploys to get people to behave a certain way, they both have found they are very accurate inShow MoreRelatedEssay on Smoking in America1122 Words   |  5 PagesSmoking in America In the United States today, more than forty six million Americans are addicted to cigarettes. More people have died due to cigarette smoking than from narcotic drugs, World Wars I and II, and the Vietnam War combined (Bailey 1). The annual death toll for cigarette smoking is more than four-hundred thousand Americans a year, and is the number-one preventable cause of death in the United States. If Americans are aware of the lethal effects of smoking, why is it still so popular?Read MoreThe Dark Side of Advertising1741 Words   |  7 PagesThe Dark Side of Advertising Woolworths, the Fresh Food People! Oh, what a feeling, Toyota! I’m lovin’ it! †¨These are the indestructible jingles that the world of advertising has managed to drum into our heads, over the course of time. Effective? Yes. Escapable? No. Teenagers in contemporary society are exposed to up to 3000 ads per day, meaning that we are constantly bombarded with advertisements from the minute we step outside our bedroom door. As promotional agencies increase their exposureRead MoreThe Media And Its Effects On Teen And Young Undeveloped Brains1237 Words   |  5 PagesThe advertising business views teenagers in society as a viable market section, due to their immature understanding of the media and its dazzling impact on teen and young undeveloped brains. The media is progressively specializing in children and adolescents to captivate with advertisements. according to market research corporations, teenagers are vital to marketers because they can pay a considerable open income, spend family cash easily, and they are easily able to influence their families to spendRead MoreVisual Ad Analysis On Video Games1577 Words   |  7 Pagesrevolves around technology. From smartphones to social media, we cannot escape the digital world lurking around us at every moment of the day. One of the takeaways of the digital age that we are living is the effect on America’s youth. They are constantly being bombarded with pixels on a screen. As video games and television become more and more violent and realistic, adolescents become wrapped up in the virtual world instead of reality. A quote from Tom Bissell reads,â€Å"We are no longer worried that childrenRead More Sexually Explicit Advertising is Detrimental to Society Essay1700 Words   |  7 PagesSexually Explicit Advertising is Detrimental to Society Just how far should advertisers go to sell a product? Individuals are reminded that a new age in advertising has emerged when Britney Spears and Victorias Secret model Tricia Helfer grace the cover of Forbes, a traditionally mature financial magazine. However, as any good advertiser knows, sex sells; all people need to do is look at a newsstand or magazine rack. But while it sells, it also offends as the promiscuous use of sexual imagesRead MoreThe Media And Its Impact On Society1161 Words   |  5 PagesThe media plays a significant role in developing awareness on various different subjects. Without the media, people would be much less informed on many social and economic issues. The media can be credited for improvements in these sectors today as it engages the public to have an opinion of our on-going evolvements by releasing daily reports on such topics. In terms of charitable aid the media has greatly developed our awareness with a nature that influences us to feel sympathy fo r those less fortunateRead MoreHow the Media, Violence, and Advertising Effects the Minds of Young Children and Adults1036 Words   |  5 PagesMedia, Violence, and Advertising Effects the Minds of Young Children and Adults Media, it’s everywhere you go, and plays a major role in our everyday lives. It’s the largest source of entertainment and the most powerful and influential invention in the twentieth century. The amount of violence and advertising seen in the media has posed a lot of controversy, and many studies have made clear that the media is responsible for much of the violence seen in our world we live today. Many of our televisionRead MoreAdvertising And The Global Epidemic Of False Advertising854 Words   |  4 PagesTelevision, magazines, phones, and Internet all contribute to the global epidemic of false advertising. Millions of Americans have a television or the most current news in there home, which contributes to society always wanting to be someone their not. On the contrary it is a great way to spread important news but consequently ads are showing the reality of how to promote stereotypes or have products we don’t need. As a consumer we get bombarded with ads fo r different services or products that justRead MoreMarketing And Advertising Of Fashion Marketing Essay1413 Words   |  6 PagesToday, marketing and advertising play a critical role in the fashion industry; they are various activities involved in building consumer relationships and stimulating consumer purchases by satisfying their needs. The primary goal of fashion marketing is evident: supplying the right merchandise, to the right customers, at the right time, in the right place. Often confused as marketing, Advertising is a subset of marketing; it is a single component of promotion in the marketing mix. The process ofRead MoreThe Negative Effects of Television on Children in Society Essay1308 Words   |  6 Pageswatch 28 hours per week. The effect of television creates negative development in children. Television is one of the biggest contributions to the growing amount of obese children in North America. The amount of glorified violence in today’s society can be att ributed to children watching high rated television shows. Many young children are involved in promiscuous behaviour. This might be a result of what they had seen on a television program. A good deal of advertising companies advertise on children’s