Water Wheels in VPython

by Colleen Williams

Abstract

Water wheels are versatile tools that do work with the energy they get from a moving water source. The wheel iteslf combined with the structure that carries out some sort of work is what we call a mill, some examples being a sawmill and flourmill. In this project, I aim to demonstrate how a steady source of moving water allows for a wide variety of work can be done. Examples of rotational work are a flour mill and what is called a triphammer, whose functions are able to differ because of the idea of gear ratios, and the Hierapolis mill, which creates linear motion instead of rotational.

Click on the images to activate the animated gif

Water wheels function in a way analogous to modern-day machines. 
                                                         
Bicycles use gears of multiple sizes to accommodate for varying terrain.                    The back-and-forth motion of some mills is comparable to engines and their pistons. 
Source:http://bicycleuniverse.info/eqp/gears.html                                                 Source:  https://www.reference.com/vehicles/four-stroke-engine-work-2ec8d5f1dff0c977
Water wheels are even a point of interest in the modern world, as this article shows.

Table: Water Mill Type and Gear Ratios
Mill Type Gear Ratio
Trip Hammer 1:1
Flour Mill 4:1

Flour Mill


Here is a model of a flour mill. The wheel is turned by water and, through a crown (larger gear) and pinion (smaller),turns a stone that grinds grain against another stone.

Trip Hammer


The trip hammer, in contrast to the flour mill, makes an emphasis on torque rather than velocity. Trip hammers use cams instead of gears to determine how many times the hammer is lifted per wheel spin. The cam is the small appendage on that causes the hammer to rotate. In the case of engines, cams are used to push what is called a rocker arm, which opens and closes valves that let air in and exhaust out. This particular hammer has one cam.

Hierapolis Mill





Because the Hierapolis mill has not been a success yet, here is a link to a model- Source: http://www3.rgzm.de/ephesos/
    Some Advice for Future Students
    • Keeping a journal really helps when it comes to writing the narrative because it tells you which parts of the project were made in which order.
    • The "angle" command in VPython is confusing and limited in the angles it allows a box to turn, according to my experience. Best to use "up=(x,y,z)" and figure out which direction width, length, and height refer to.
    • Extrusions can belong to a frame; 2-D shapes cannot.
    • Sometimes an error will prevent code from being compiled. If a word is highlighted that doesn't appear to be the error itself, the problem may be forgetting to close teh previous pair of parentheses.