Riding the wave

For Berkeley engineer Reza Alam, deeply immersed in researching ocean waves, the hot, dry, landlocked city of Yazd, Iran, might seem an unlikely birthplace. But it was here that Alam’s childhood love for science grew and brightened like the evening stars he studied through binoculars every night.

Mechanical engineer Reza Alam is testing theories about “cloaking” ocean waves in the wave tank at the Richmond Field Station. (Photo by Thomas Walden Levy)Mechanical engineer Reza Alam is testing theories about “cloaking” ocean waves in the wave tank at the Richmond Field Station. (Photo by Thomas Walden Levy)Now an assistant professor of mechanical engineering, Alam contends that objects at sea can be “cloaked” or shielded from surface waves. While his research is still in the early stages, some academic colleagues believe his discovery could one day help shield oil drilling platforms, wind turbine towers or sea-borne data-collecting buoys from rough seas. And what’s more, Alam says the sea floor structures he envisions constructing to calm surface waves could be built at low cost.

This cloaking strategy relies on Alam’s observation that certain seafloor topographies can guide ocean wave energy from the surface to the thermocline, the watery membrane separating warmer and more turbulent surface water from cooler and deeper waters.

To take advantage of this effect, Alam suggests that in water 100 meters deep or less, sea-floor topography can be tuned, by adding boulders or synthetic materials, to guide the energy of broad sets of surface wave frequencies through a nonlinear resonance mechanism to the underlying thermocline.

Alam’s work shows that when this occurs, the surface water above the thermocline calms, as the surface wave energy is transmitted deeper within the body of water. If desired, a second sea floor structure could also be built to return that energy to the surface beyond the shielded structure.

Ironically, it was Alam’s fascination with the stars that put him on the path to working with waves and the science of fluid dynamics. As a child he studied astronomical events through binoculars, and later through his high school’s Celestron telescope. To become an astronomer, he was counseled to study physics, which he did, mastering a college-level physics text before graduating from high school.

Accepted to the prestigious Sharif University in Tehran, Alam pursued an undergraduate degree in mechanical engineering because the mechanics side of physics is what grabbed him the most. He then earned a master’s degree at Sharif in applied mechanics, while studying problems in nonlinear dynamics and waves, work that led to his acceptance into the doctoral program at MIT.

Alam credits Dick Yue, his Ph.D. advisor, for inspiring him to craft clear ways to communicate his ideas—not just in well-written papers, but also with easily understood explanations for non-scientists. Alam also learned that his creativity is nurtured by a wide-ranging curiosity.

“Multidisciplinary thinking is very important,” says Alam. “The idea of [ocean-wave] cloaking came to my mind because I was reading papers about electromagnetic cloaking. I didn’t have to read those papers, because I work in fluid mechanics. But then I read them and started thinking: can we do something similar in fluids?”

Topics: Mechanical engineering, Development engineering, Devices & inventions