Engineering Now 2009

Engineering Science and Mechanics (ESM)

When the 20,000-gallon towing tank sprung a leak, it could have been curtains

In the basement of Norris Hall sits the towing tank, a huge below-ground behemoth that, when filled with water, allows researchers to complete any number of experiments involving the effects of water on model ships, boats, and submarines.

Built in the early 1960s, the tank can hold 20,000 gallons of water. With the pull of a lever or two and the push of some buttons, the tank comes to life. Subtle or substantial waves and turbulence will interact with a model being pulled — or towed — through the water. The experiments can simulate the bouncing of a model ship, helping engineers build a better, larger vessel for actual marine use.  It's the ultimate game of Battleship, with the goal of some of the experiments to determine the conditions that will sink a vessel.

The tank is shared by the engineering science and mechanics (ESM) and the aerospace and ocean engineering departments. Both consider it a vital resource to a number of lab courses, and as a unique lab set-up among universities (the tank runs the length of a massive basement room floor). Yet, the tank was in danger of being shut down more than a year ago. It sprung at least one large leak and was pouring water out at a rate that drains in the floor could not keep up with. The problems were numerous.

ESM head Ishwar Puri and other faculty within the department saved the tank with funds from the student engineering fee fund. Although the budget for repairs was set at $100,000, careful use of the funds brought the final expense below $60,000. And not only was the tank repaired, but it was improved: new observation points were built into the tanks. These now allow researchers, graduate and undergraduate students, and visitors to study the motions of ships and submarines using noninvasive means of measurement. Now, instead of placing bothersome probes and other devices on models that interfere with the vessel's movement, researchers can measure a ship's performance by using lasers and lights directed through the cut-outs. Puri said this provides a truer record of how the actual vessel will perform in real wave environments, since a ship or submersible at sea will not have the probe appendages attached to it.

Virginia Tech students and researchers are not the only ones who get access to the tank. During the summers, it is used in a program that brings school children to campus to build and then test remote- controlled model boats in the water. Mac McCord, a mechanical engineer in the ESM department, who operates many of the labs, said the experience is not only fun for the children, but vital to Virginia Tech. “Those kids are our future engineers.”

The tank is due for further repairs and updates, including new controls. The trick: finding someone who can revamp the unique tank, McCord said.

The student engineering fee has gone to other uses in ESM, not just the towing tank. A third-floor lab classroom has been renovated with new electrical outlets along the floor and Internet connection boxes along the wall so that students can use the Internet on their laptops and tablet PCs. On the first floor, inside the materials characterization lab (affectionately called the “busting lab” by students), various objects, such as soda cans (full and empty), are squeezed, pulled, stretched and otherwise pulverized as students learn the strength of different materials. Almost all of the equipment in this lab was more than 20 years old and had faltering motors and sensors. With fee money, the machines were gutted and outfitted with new motors, digital sensors, and other features that bring them up to current standards, McCord said.

Other labs, including an instrumentation lab and a fluids teaching lab also have been updated with the latest equipment. In the former lab, students tinker with various objects, for instance, recalibrating a commercial fan so that its speed accommodates the amount of airflow that is required. In the fluids lab, students learn about the effects of water on a body, including how a boat moves through water.  New computers also have been purchased for various labs that use high-end software that did not communicate with older computers. A lab dedicated to the effects of vibrations on objects — faux earthquakes on model houses or buildings, for instance — will be updated with new equipment, said Muhammad Hajj, an ESM professor.

The fee helps the 101-year-old ESM department ensure that Virginia Tech maintains itself as a “cutting-edge integrated research and education institution,” Puri said.