The interference resistance, i.e. the total resistance minus the sum of the resistances due to substructures can reach up to 10 % of the total resistance of a submerged body. That for it is usually called parasite drag. This problem relates to fin and sensor systems of submarines, ROVs and AUVs. The reduction of the interference resistance is one aim of every design process of submerged bodies.rnSVA Potsdam has initiated the R&D project “Interference phenomes of substructures of submerged bodies” to investigate this parasite drag. In this project systematic numerical and experimental investigations were carried out with bodies of a submarine and an AUV. The most influencing parameters were variated: speed and depth of the submerged as well as the chord length, the span, the aspect ratio and the position of the substructure on the bodyrnThe numerical calculations were validated by model tests. Numerical calculations were performed for full and model scale to evaluate the scale effects. The model tests included the determination of the forces of the submerged bodies as well as detailed flow visualization of the flow around the substructure with PIV measurements.rnAs a result, the interference resistance can be quantitatively determined using systematic sets of parameters for a submerged body with substructures. The flow visualization shows details of the flow on its transition from the substructure(s) to the body. This gives an indication of the causes for increasing or decreasing interference resistance as "parasite drag".
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