I believe that my biggest take away from this Mini Project is related to how assumptions during the process can influence modeling and theoretical computations. The assumptions made primarily during solution of velocity and pressure analysis, such as incompressibility of fluids, the insignificant velocity change of fluid during launch and small potential energy values made the solution much easier for me to digest. This is the first time that I have been pushed to really grasp how these assumptions are negligible, and why that can be the case. Of course, the outcome may not be as accurate as it could be, but that comes at the expense of reducing computations to an introductory level.
Beyond that, during the design challenge portion of the exercise I became much more intimately familiar with what the drag force is, and how difficult it is to compute analytically compared to wind-tunnel testing. Understanding what goes into deciding on the drag coefficient for a complex body such as a rocket was minimal prior to this project. Although there is still room for further understanding, I am now better prepared for future projects that involve objects moving through a fluid.
How the aforementioned points might apply to real-life practice is beyond the educational scope. Although it is undeniable that I now have a greater understanding of how density, temperature and pressure of a fluid are related and how to manipulate the variables for flow considerations; I do not believe that was the greatest real-world benefit for me, from this project. This project required me to start from a baseline knowledge near zero, approach a problem, and quantitatively define and explain the intricate process. This benefit of practicing solving a complex problem cannot be understated. The usefulness of being able to define and solve a problem is what should define an engineer, and not the ability to plug values into appropriate formulas; but to be able to reason out what formula is needed to describe something complex.
This mini project allowed me to understand the modeling of a simple equipment such as a water bottle rocket and understand the dynamic and static components associated with it. A major component of my contribution came in the form of performing the necessary computations and understanding the rocket trajectory, assumptions which my teammates had made as well as performing and understanding the ABET guidelines pertaining to the project. It allowed me to understand parameters, derive equations and validate these equations graphically. Since I was interested in the thermodynamics aspect of the bottle, I also studied the adiabatic expansion of the air inside the bottle rocket and its impact on the temperature of the air inside the rocket, if the pressure was kept constant.
The analysis and challenge phase allowed me to study the various forces acting on the bottle rocket as well as allowed me to derive equations for velocity and thrust of the rocket. The Challenge Phase allowed us to explore ways of reducing the amount of drag on the rocket. There was an extensive research performed on turbulent flow of air and the various points on the rocket where the drag force is concentrated and allowed me to derive an appropriate drag coefficient for our calculations. This especially taught me a lot about data acquisition and computation, and I will certainly retain the lessons learned from this.
The knowledge acquired in this assignment have certainly helped in my understanding of fluid mechanics, predominantly aspects of turbulence, laminar flow, exit velocity as well as drag. This is especially applicable in real life since I have now learned the theory behind why certain equations are used and how others are derived and that will help me make informed decisions on the usage of equations as an engineer in the real world, particularly those related to aerodynamics.
Applying some of the principles learned in lecture as well as supplemental information we learned on our own outside of class helped with knowledge retention. Professor Liebenberg always says that the best way to learn is self-guided learning. After this project, I would say that he is right; self-guided learning is a great way to learn. Reading scholarly articles, other textbooks, and published academic papers helped with getting a broader picture of things. Listening to a professor talk about a topic a couple times a week gives you only his point of view. I think that seeing how other people view a topic and comparing it to your own viewpoint is key.
Over the course of this project, I learned many new things. Not being given all of the information in class encouraged me to learn what was needed to complete this task. While looking for this information, I found more than what was needed. I learned how to measure the thrust of a rocket-like system and that it is the measurement of the expulsion of mass. This amazed me because I had no previous experience to this type of force. I also learned that Benoulli created an equation that simplified fluid flow. This equation helped with the calculation of energy within the pressurized bottle. When analyzing the ideal shape of a rocket, I learned a great deal about drag. What struck me was that rockets and planes have different drag properties when going either below or above the speed of sound. In our case, the water-air propelled rocket is not breaking the sound barrier so we only had to deal with the subsonic properties.
The principles and techniques that were required to complete this project will come in handy in real-life engineering practice. Being a civil engineer, I will be using Bernoulli’s fluid flow equation a great deal. Any fluid pressure application that I may face in the real world will be solved using the principles I used in this project. Aside from the technical aspect, the proper team dynamic will always be useful in the real world. Being able to get along with team members and work together to a common goal is crucial in any setting.