It's Just Rocket Science!

In high school physics class, students learn how to calculate the speed and acceleration caused by forces acting on an object and the forces that occur when objects interact with one another. But what happens when you have a constant stream of fluid on an object? How can you calculate and analyze the force applied by a fluid?

The answer is through the study of Fluid Mechanics. It was my favourite course last term. I think it is really cool to be able to analyze the pressure and forces that a fluid will exert on an object and it is useful for so many different applications!

Fluid mechanics is used in the design of the following:

-Rocket Science – It is a knowledge of fluid mechanics that allows engineers to design rockets. They need to determine how much gas must be produced through combustion to propel the rocket at the acceleration that it needs.

-Aerodynamics of cars – The shape of a car can drastically change its performance. Cars are designed to allow the air to flow smoothly across them without creating too much drag (which really slows cars down). A car without much drag is much more fuel efficient – so this is pretty important!

- Environmental water systems such as dams – A dam has to be built to be strong enough to support the weight of the water it holds, so it is really important to be able to calculate how much force the water will exert on the dam

-Air planes – What makes a plane fly? Fluid Mechanics! The shape of planes’ wings are designed so that when the air passes around them, more force is exerted on the bottom of the wing and this pushes the whole plane upwards. Without a knowledge of fluid mechanics we definitely wouldn’t have the amazing huge planes that we have today.

As you can see, fluid mechanics has a lot of important applications, which makes it pretty interesting. Plus, it's pretty cool to be able to say that you really are studying rocket science!

The Man and the Banana Peel

An interesting thing happened on the bus ride to work today...

In the downtown area of Waterloo, A man ran to catch up to the bus, and the driver stopped for him. As the doors were opening, the man took one last bite of his banana and dropped the peel on the grass beside the bus. If he had taken the time to look, he would have known that there was a garbage can about 6 feet behind him. When he climbed inside, the bus driver made a comment about picking up the banana peel, and they got into a bit of an argument. He refused to pick it up and took his seat in the back.

He claimed that the banana peel was not garbage. His arguments were that the peel was biodegradable, and that back in history, people did that every day.

She claimed that it was indeed garbage, and that we have littering laws and garbage cans at bus stops for a reason.

This whole thing got me thinking about our morals and priorities as a society. That banana was completely organic, and it's true that it will decompose, but it would take weeks to completely disappear back into the earth as soil. I imagine that a city worker will probably pick it up off the ground as 'garbage' before that time comes anyway. So did he do the right thing? His argument that people did it all the time back in history may be true, but I don't feel that it's a valid argument for his case. There are dozens of things that people did hundreds of years ago, but we would never do those things today. Examples: living in caves, never shaving or bathing or cutting our hair, accusing gifted women of being "witches" and burning them at the stake..

Sure, those examples are a bit extreme, but I got my point across. In the middle of a forest it may be different, but it's generally unacceptable to throw a banana peel on the grass in the middle of the city. Would you be happy if someone dumped some banana peels on your front lawn?

So then I take the other side of the story. If he had dismissed that peel as garbage, and thrown it in the garbage can, then it would have gone off to a landfill. Rather than being put into a compost container and left to decompose in a "proper" place, it would just be another piece of garbage clogging up the landfill, forcing the city to eventually increase the size of its landfill and smother many more natural greenspaces with piles of garbage. Having only a garbage can with no recycling bin or compost at that bus stop forces any passersby to classify their waste as garbage, unless they want to hold onto the waste until they reach a better spot down the street. Perhaps it's the city's fault for not providing the options.

The whole ordeal reminded me of SE 101, a course that I took in first term. ("SE" stands for Software Engineering). We looked at a few case studies of example situations where the person involved had to make a tough choice, and their ethics were what helped them through.

Engineering is all about designing and planning and building to improve the world we live in. As engineers, it's our job to make the right decisions and know where we stand. So who was truly "right"? This kind of reminds me of a possible PDEng assignment topic, eh? :)

So my train of thought got stuck on its tracks. I don't feel that there really was a "right" thing to do in that situation. What do you think?

Design of a Culvert Crossing

I am a current first year environmental engineering student. The final project for our 'Introduction to Civil & Environmental Engineering' course involved the predesign of a culvert crossing on campus. A culvert is a tunnel that allows water to pass through. They are often used to allow water to pass under roadways.

Currently there is a by-pass channel (flowing body of water) on campus. There is a crossing with two steel culverts that allows water to flow under the crossing. The project was to develop a more advanced culvert system that would be able to handle a greater amount and speed of water. The replacement culvert was to be designed to stand up to a hundred year storm. A hundred year storm is the largest storm that would be expected to occur in the area within a hundred year period.

We spent hours outside surveying the site. We recorded the elevations of the land around the channel and even put on waders and surveyed through the channel. We recorded the distance between all points so that they could accurately be plotted on an AutoCAD map.

Once the data were collected we created a map of the area, and developed a design for a replacement culvert. We had to consider the quantity and speed of water from a hundred year storm.

The project was very open ended. It was up to us to specify the finer details of the proposed crossing. We had the option of designing a sidewalk and guardrail if we thought it was necessary and we had to determine a suitable road width based on how much traffic the site sees. We had to compare the efficiency of 5 different culvert diameters and the number of culverts was completely up to us.

Ultimately, the design that I proposed included 6 culverts, each having a 1.2 meter diameter.

Through the experience, we all developed our surveying and autocad skills, and learned about report writing.