Aerodynamics of Saccate Pollen and its Implications for Wind Pollination

Matt Clemente, Mechanical Engineering (on left in photo)

Faculty Mentor: Dr. Lisa Marie Grega

In Collaboration with Dr. Jeffrey Osborn

              The research done on saccate pollen at TCNJ during the summer of 2007 is part of a larger project comprised of scientists from around the country. This research looked at the possible aerodynamic effects produced by air-filled sacs on certain types of pollen. This research was the continuation of research done previously in the Spring semester of 2007. The goals of this summer were to refine the current experimental methods for analyzing the aerodynamics of pollen and probe into the significance of certain surface features pertaining to the aerodynamics of the pollen grains.

              All experiments during the latest stage of research were done utilizing a drop tank. A drop tank is as simple as it sounds, it is a tank of a fluid that objects are dropped in and have only the effects of gravity to pull them down. This type of apparatus is useful in studies where a low Reynolds number is desired. A Reynolds number is a dimensionless number that describes the ratio of inertial to viscous forces on a object using the characteristic length of the object, the relative velocity of the object to the fluid, and the viscosity, how thick or thin, of the fluid the object is flowing in. Reynolds numbers are used to scale from a real life situation to something producible in a lab. There has not been much research done at low Reynolds numbers beyond spheres and spheroids. The experiments done this summer created background information on spheres to determine whether or not roughness or texture of an object affects its coefficient of drag at low Reynolds numbers. Coefficient of drag is another dimensionless number. It is useful in comparing drag forces among different geometries. This information will then be used to further refine the models of pollen that are to be used in drop tests. Repeated drop tests will reveal the coefficient of drag of saccate pollen. This value will then be compared to the coefficient of drag for saccate pollen without their sacs.

Personal Statement

              This research has made me realize many of the troubleshooting skills needed to be successful in a lab. I used many lab tools this summer including some that were actually made in house by my research partner and myself. These tools have furthered my skills in accurately determining mass, volume, density, specific gravity and velocity. Troubleshooting was a key factor in determining these values because certain apparatus are not readily available. Troubleshooting was also important in the refining of drop tests to be sure our results were significant.

              The SURP Program also opened my eyes to various other fields of study. Weekly meetings allowed for fellow undergraduate researchers to describe what they were researching and where they were going to take it. These weekly meetings provided a break from the monotony that can be experienced when running an experiment repeatedly for hours.