Engineering professor and world-renowned expert on fluid mechanics Graham Wallis delivered the College's seventh annual Presidential Lecture yesterday afternoon to a crowd of about 150 in Alumni Hall in the Hopkins Center.
The lecture, titled "A Smorgasborg of Multiphase Flow," presented a broad, basic survey of fluid mechanics.
President James Freedman, who introduced Wallis, said, "The Presidential Lecture Series is designed to recognize the contributions of members of the faculty to Dartmouth's academic excellence."
Wallis currently holds the Fairchild Professorship at Dartmouth, and served as associate dean of the Thayer School of Engineering from 1989 to 1993.
Wallis discussed multiphase flow, which is the study of fluid behavior in which a combination of suspended particles, liquids, gasses or plasmas travel together and react with each other.
Examples include pouring whiskey over ice cubes, burping, stirring milk into tea, clouds, soda, blood, beer and pollution.
Wallis said for many diseases, including pneumonia, kidney stones and allergies, "multiphase flow is the primary cause or symptom."
The lecture was accompanied by an extensive slide show.
Wallis discussed experiments on multiphase flow conducted by several local companies, some of which were started by Thayer School of Engineering graduates or faculty.
Multiphase flow research examines such diverse topics as pressure zones around ski jumpers, chemicals that dissolve blood clots after heart attacks and air vortexes that cause dirt to build up on rear windows of cars.
Wallis spoke of different models researchers use to help predict the behavior of systems. The first, called a homogeneous mixture, treats the elements of the flow as one entity, "rather like beer flowing from a keg," he said.
Another model, separated flows, is used to explain the familiar phenomenon called slug flow, which occurs when soda is poured too quickly from a narrow necked bottle.
Wallis has received numerous awards for his work from such organizations as the Institution of Mechanical Engineers and the American Society of Mechanical Engineers. In 1990, he spent a term in London as a Royal Society Visiting Fellow.
Freedman created the Presidential Lecture series in 1987.
