Aerodynamics of Vehicles and Airplanes, and Hydrodynamics of Ships - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 114

Fig. 7.6 Wave output of an
inland tug boat with a pre-
coupled barge, depending on
flow plate application

1600

short flow plate with a relatively
high hydrodynamic resistance

1200

800

long flow plate with low
hydrodynamic resistance
and high efficiency

400

0

56 7 8 9 10 11 12 13 14 15 16

-1

velocity [km*h ]

Using a long rigid-foam wedge flow plate decreases hydrodynamic resistance
and wave output at the same ship's velocity by up to 10-20% [ 28 ]. Similar to sea-
going ships, the inland ships' contours must be designed and kept smooth to
decrease draught. A clean outer surface can decrease fuel consumption by up to
15% compared to a dirty outer surface [ 29 ]. Erosion on the outer surface of the hull
can be recognized with an optical under water observation device [ 30 ].
Bow thrusters improve maneuverability and decrease fuel consumption.
Transversal propulsion devices built into the bow of a ship make the ship more
maneuverable. Bow thrusters make docking easier, since they allow the captain
to turn the vessel to port- or starboard without using the main propulsion
mechanism [ 31 ]. Stern thrusters are fitted at the stern and operate in a similar
manner [ 32 ].
In inland shipping, operating near cities with high population densities, direc-
tives require an exhaust gas emission level as low as possible. That assumes the
use of high quality diesel fuel. Installation, inspection, and maintenance of exhaust
gas after treatment systems are playing an increasing role. Depending on the ship's
course and geographical coordinates of harbors, inland ships emit pollutants near
big cities. To protect environment and habitants, Self-Diagnosis system should be
introduced into inland shipping first.

7.4 Summary and Recommendations: Technical Results
in Aero- and Hydrodynamics

There is still a large potential for improving the aerodynamics of vehicles, air-
planes and the common hydro- and aerodynamics of ships. Both aero- and
hydrodynamics

is generally improved by smooth surfaces and compact

constructions.