Mehdi Saadat's research while affiliated with Harvard University and other places

Publications (9)

Article
Full-text available
From the discovery of functionally graded laminated composites, to near-structurally optimized diagonally reinforced square lattice structures, the skeletal system of the predominantly deep-sea sponge Euplectella aspergillum has continued to inspire biologists, materials scientists and mechanical engineers. Building on these previous efforts, in th...
Article
Fish benefit energetically when swimming in groups, which is reflected in lower tail-beat frequencies for maintaining a given speed. Recent studies further show that fish save the most energy when swimming behind their neighbor such that both the leader and the follower benefit. However, the mechanisms underlying such hydrodynamic advantages have t...
Article
Fish migrate across considerable distances and exhibit remarkable agility to avoid predators and feed. Fish swimming performance and maneuverability remain unparalleled when compared to robotic systems, partly because previous work has focused on robots and flapping foil systems that are either big and complex, or tethered to external actuators and...
Article
Biomechanists and biologists alike have yet to fully understand the complex morphology and function of shark denticles, morphologically intricate tooth-like structures embedded into the skin of sharks. Denticles vary in many ways (such as size and shape) depending on shark species, and studies on denticle hydrodynamics have suggested that they may...
Article
Full-text available
There have been significant efforts recently aimed at improving the aerodynamic performance of aerofoils through the modification of their surfaces. Inspired by the drag-reducing properties of the tooth-like denticles that cover the skin of sharks, we describe here experimental and simulation-based investigations into the aerodynamic effects of nov...
Article
We present unifying rules governing the efficient locomotion of swimming fish and marine mammals. Using scaling and dimensional analysis, supported by new experimental data, we show that efficient locomotion occurs when the values of the Strouhal (St) number St(=fA/U) and A*(=A/L), two nondimensional numbers that relate forward speed U, tail-beat a...
Article
Full-text available
Occupancy-driven heating and cooling technology, in which novel sensing systems extract information about the occupants to more strategically and effectively deliver comfort based on occupants' needs can make the designers achieve the goal of energy efficiency. Programmed thermostatic control operates on a predefined setback schedule, the house or...
Article
A computational study has been conducted to address the formation of vortex rings ejected from a weakly flexible nozzle at the end of a piston-cylinder device. The first observation is that, regardless of flexibility, for small enough duration of a push on the piston, the negatively-signed induced vorticity on the outside of the cylinder merges wit...
Article
Full-text available
A computational study was conducted to explain the aerodynamic effect of leading edge tubercles on maximum lift coefficient, stall angle of attack (AoA), drag, and post stall characteristics for airfoils as well as finite wings. Past experiments demonstrated airfoils with leading edge tubercles do not improve Clmax, drag, or stall AoA but smoothen...

Citations

... These square lattices are reinforced with diagonal struts which increases the buckling response of such designs under the high pressure from the surrounding water. The diagonal reinforced struts also help to increase the vibration absorption properties, which are generated during the vortex formation when water tries to pass through the pores of the biological structure [44]. Together horizontal, vertical and diagonal struts, interconnects in a manner that makes an array of alternating open and closed cells and generates an optimal strutbased design [9]. ...
... The key to understanding fish-schooling behavior lies in making clear the role of fluid medium or flow structures [120][121][122][123]. A single fish can be a good analytical entry point. ...
... Recently, research on biomimetic robots has been receiving significant attention [1][2][3]. Various studies in robotics are inspired by the natural mechanisms in living organisms, including birds, fishes and insects [4][5][6][7]. Notably, this biomimetic research is not limited to only robots. Biomimetic sensors have also been receiving considerable attention as natural sensing mechanisms may inspire the development of new sensing technologies [8][9][10][11]. ...
... Shark-skin-inspired riblets have been shown to reduce the drag by modifying turbulence over surfaces [7][8] . In addition to drag reduction, shark-skin denticles could generate lift and increase the lift-to-drag ratio, but the performance is significantly deteriorated with larger denticle size [9][10] . American golden plover can fly more than 4 000 km over the ocean and loses only 0.06 percent of its weight per hour [11] . ...
... Shark-skin-inspired riblets have been shown to reduce the drag by modifying turbulence over surfaces [7][8] . In addition to drag reduction, shark-skin denticles could generate lift and increase the lift-to-drag ratio, but the performance is significantly deteriorated with larger denticle size [9][10] . American golden plover can fly more than 4 000 km over the ocean and loses only 0.06 percent of its weight per hour [11] . ...
... The references show that the optimal swimming performance can be obtained when St is between 0.2 and 0.4 and the tail wave amplitude/body length (A/L) is between 0.1 and 0.3 (H. Liu & Curet, 2018;Saadat et al., 2017). The constraints of multi-objective optimization are as follows: ...
... e refrigeration type and delivery mechanism, including such as air conditioning, material handling, fan circuits, air vents, and water pipes, all impact the distribution network [18,19]. Most of the studies in the literature deal with energy management systems for nonresidential buildings [20,21]. A smart HVAC system offers significant benefits over a traditional heating system, such as reduced energy consumption, ailment maintenance, predictive performance problems, and distant and automatic framework alterations. ...
... This is done with the objective of keeping the effects specific to the tubercle-like variations independent from the choice of the airfoil, planform area, and chord Reynolds number. The NACA 0020 was chosen as the baseline airfoil in order to mimic experiments in the literature which observed a 20% thickness-to-chord ratio in the humpback whale species Megaptera novaeangliae. 1 Other investigations into these effects have been performed using NACA 63 4 021, 4 0012, 21 and 0021 3 profiles. It is well known that the thickness and leading-edge curvature of an airfoil have a strong effect on maximum lift and the severity of the stall regime. ...