High speed gas flows occur during the movement of aircrafts, rockets, and descent vehicles, as well in combustion chambers, nozzles, many other technological applications [...]

there are different methods to reduce drag in high speed hulls. one of these methods is a change in the shape of the body by adding longitudinal side tunnels. in this paper it has been attempted to determine the influence of the tunnel height on hydrodynamic characteristics of the hull to achieving an optimum shape for the tunnel. to achieve this purpose, numerical simulation of the problem has...

high speed trains are an indispensable part of rapid transportation systems in many countries. as the fastest means of transport on the ground, these trains are extremely sensitive to the terrain and track conditions. geometrical irregularities and mechanical characteristics of the track, together with inconsistencies in the lane (including bridges that support the track) are considered importa...

There are a large number of identical purchasers of boat rentals, none of whom own a boat, and whose utility from a boat ride depends on the weather. The state of the weather can take one of four values s = +2,+1,−1,−2. In state s, the utility of a renter is βs log t− p.t where β is a positive number, t is the amount of time that the boat is rented for, and p is the price paid per unit time of ...

Recreational boats are a dominant feature of estuarine waters in the United States. Boat strike injury and mortality may have a detrimental effect on populations of diamondback terrapins (Malaclemys terrapin), a keystone species in estuarine ecosystems. In Barnegat Bay, New Jersey, 11% of terrapins (n = 2,644) have scars consistent with injuries from boats. Conservative estimates of injury rate...