Optimally Stable Mobile Manipulator Path Planning
Optimally Stable Mobile Manipulator Path Planning Mobile manipulators such as mechanical loaders and rescue robots consist of a moving base and a one (or multi) degree of freedom arm attached to the base. In many circumstances mobile manipulators are supposed to move on uneven terrains and may get into postures dangerous for their stability. The […]
Acoustics of Sound-holes in Musical Instruments
Acoustics of Sound-holes in Musical Instruments The present day violin is acoustically so sophisticated that 200 years of scientific study has not been able to systematically distinguish between a good and an average violin. The present-day violin making is based on replicating old Italian violins widely accepted as perfect instruments; a perfection that is reached […]
A caravan of fast ships in a wide rough canal
A caravan of fast ships in a wide rough canal It is known that when a boat advances near critical speed in a wide canal, solitons can be radiated upstream in a transient manner. Real canals are not flat, therefore we considered a canal with a randomly rough bed. Governing equations were shown to be […]
Wave-Mud Interaction
Wave-Mud Interaction Damping of the ocean surface waves as they propagate over and interact with the muddy seafloor plays an important role in coastal phenomena. Fishermen of southwest coast ofIndia in ”Chakara” feast celebrate the arrival of mud banks that damp large monsoon-driven waves and calm onshore waters resulting in a rich fish harvest. “1998 […]
Feedback Control of Separation in Unsteady Flows
Feedback Control of Separation in Unsteady Flows Separation of flow is responsible for most of the form drag on airplanes, stall in turbine blades and vortex shedding and vortex induced vibration of objects placed in fluid flow. Controlled separation, however, has practical applications and is used, for example, to enhance the mixing efficiency in combustion […]
Ocean wave energy
Ocean wave energy World-wide demand for electricity is expected to double within the next 20 years; this, combined with commitments to significantly reduce CO2 emissions in the same time-frame are increasing the search for clean, socially acceptable methods of generating power. Ocean waves are a large, relatively untapped renewable energy resource. According to London-based Carbon […]
Ship wave resonance in stratified seas
Ship wave resonance in stratified seas Waves of an unsteady disturbance in a 2-layer fluid Oscillation of underwater vehicles (particularly submarines) in littoral zones, where water is more likely to be stratified, generates particular waves that can reveal information about size, speed and the depth of the vehicle. We studied the mechanism behind the generation […]
Localization over a Random Bottom
Localization over a Random Bottom Localization of Internal Waves by Random Topography If waves travel over a random bathymetry, strong spatial attenuation occurs due to multiple scattering (c.f. Anderson localization in solid-state physics). Unlike Bragg scattering where strong resonance occurs for a discrete set of frequencies satisfying the Bragg resonance condition, spatial attenuation takes place at nearly […]
Bragg Resonance
Bragg Resonance with Regular Topography Bragg Resonance in a 2-Layer Fluid Real ocean density is not constant and varies with the depth (due to change in water temperature and salinity). In most oceans, density jumps from a lighter upper layer fluid density to a heavier lower layer fluid one over a surface called Thermocline. Waves – […]
Wave Carpet
Wave Carpet: An Efficient and Multidirectional Ocean Wave Energy Converter Project in the News Synopsis Did you know that we can use the power of ocean waves to generate electricity and fresh water? At UC Berkeley we are developing a new Wave Energy Converter that is able to efficiently harvest this energy. The design was inspired by […]