*4.3. Interaction E*ff*ect between Hull and Accommodation on Wind Drag*

In this section, wind drag acting on hull of the ship with and without accommodation has been investigated. By comparison, the obtained results of wind drag acting on hull of the ship in two different computed cases, namely hull with and without accommodation, interaction effect between hull and accommodation on wind drag acting on hull, have been found. Moreover, by comparison with the obtained results of wind drag acting on the ship with different accommodation shapes on the deck, the effect of accommodation shapes on wind drag has also been found. Figure 9 shows wind drag acting on the ships with different accommodation shapes on their decks in head wind. A detailed comparison of wind drag acting on the ships is shown in Table 8.


**Table 8.** Wind drag acting on hull with different frontal accommodation shapes.

The results, as shown in Figure 9, show wind drag coefficients acting on the ship with different frontal accommodation shapes. The results show drastically reduced wind drag acting on the ship by developed frontal accommodations N2 and N3. Table 9 and Figure 10 show detailed differences of wind drag acting on the ship in comparison with those of the original one.

**Table 9.** Effect of accommodation shape on wind drag acting on the hull of the ship.


The results given in Table 9 and Figure 10 show drastically reduced wind drag acting on the ships; a reduction of up to 66.88% of the total wind drag has been obtained by developed frontal accommodation shape N3. The frontal box shape accommodation N1 and N2 are also smaller wind drag models, with a reduction of up to 33% of wind drag, as shown. The results of wind drag acting on the ships are in good agreement with the obtained pattern of pressure distribution around and over the hull surface of the ship.

Analyzing the pressure distribution around the ships is a useful tool for finding the reason behind the effects on the wind drag acting on the ship hull. Moreover, the results of the interaction effect between the hull and accommodation on wind drag are highly important from the marine container transportation point of view. Tables 10–12 show the results of the interaction effect between hull and accommodation on wind drag acting on the ship with the different frontal accommodation shapes.

**Table 10.** Wind drag acting on the hull with accommodation.



**Table 11.** Wind drag acting on independent hull and accommodation.

**Table 12.** Interaction effect between hull and accommodation on wind drag.


The results shown in Tables 10–12 clearly show wind drag acting on the ship with the different accommodation shapes in two computed cases, namely the hull with and without accommodation in head wind. The interaction effect between hull and accommodation on wind drag acting on the ship is drastically reduced due to the developed frontal accommodation shapes, as shown. The interaction effect on wind drag acting on the accommodation part is less than 10% and up to 65% of the hull part. The interaction effect on the total wind drag is about 10% of the frontal box shape accommodations N1 and N2, and up to 27% for the streamlined accommodation N3. Figure 11 shows a comparison of the interaction effects on wind drag acting on the ship with different frontal accommodation shapes.

The results show a drastically reduced interaction effect between hull and accommodation on wind drag of the model N3. The interaction effect between hull and accommodation of the original ship is higher than that of the model N3, by up to 70%, as shown. The obtained results are very useful to develop a new accommodation shape with reduced interaction effect and wind drag acting on the ship hull as little as possible.

For a streamlined accommodation shape like the proposed model N3, the interaction effect between hull and accommodation on wind drag has been drastically reduced, as shown. Most researchers are of the opinion that the streamlined accommodation is the best shape to reduce wind drag acting on the ship when in operation. However, the huge streamlined accommodation shape is difficult to be made and will also require a very high cost. Therefore, an accommodation shape which is simply made of only plat plates but still capable of producing a reduced wind drag could be a good choice for the ship building industry.
