Feature 2 |GERMANY
Leading edge technologies to simulate the
effects of hydrodynamic optimisation, for resistance as well as propulsive efficiency, the use of auxiliary energy from renewable resources and advanced simulation and energy management systems together lead the way ahead for future low energy and low emission shipping.
Hydrodynamic efficiency As TARGETS focuses particularly on cargo vessels, hydrodynamic effects are typically the prime cause of energy consumption. Other than for passenger ships where hotel loads and other auxiliary systems are large contributors, cargo vessels use up to 85% of all practically available energy for propulsion, excluding all internal losses in a combustion engine which are not part of the present study. Consequently, a focus on low drag/ship resistance and improved propulsive efficiency promises the largest gains. Adapting the operational profile to environmental influences, that is ship speed vs. sea state and wind conditions will further help to achieve a global optimum in terms of energy consumption.
Figure 2. Ship resistance decomposition in the TARGETS dynamic energy model
Ship resistance Ship resistance is made up from different components: (i) the pressure or form related wave resistance, (ii) the viscous drag, and (iii) the added resistance due to wind and waves. Due to the different causes these resistance components need to be considered at different stages of the vessel’s life cycle. Pressure related components depending on the hullform are a design feature while viscous resistance largely hinges on the surface quality, which is initially determined by production quality, the hull coating and maintenance. Especially the latter is clearly related to the operational stage of the vessel. Te same holds for added resistance due to wind and waves, which can be influenced through weather routing. Te following figure indicates the decomposition of ship resistance which is used in TARGETS to integrate this part into the overall dynamic energy modelling (DEM). With different physical
laws ruling individual aspects of ship resistance there
Figure 3. Predicted sensitivities: Bulk carrier with active propulsion (top), car carrier at 4 different speeds (bottom)”
80 The Naval Architect September 2012
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132