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Balloons and Airships
Published in James DeLaurier, Aircraft Design Concepts, 2022
Their slow pace allowed them to escort convoys of ships, and they had durations that lasted for days. This is a unique feature of airships: because lift is primarily provided by buoyancy, engine power is thus primarily used for forward motion over a wide range of speeds (including close to zero). This is in contrast to airplanes where the engine's power is continuously applied to provide the speed required for aerodynamic lift to sustain the aircraft. These are the reasons why an airship has the potential for very long durations as well as loitering capability. Such desirable features, as well as energy efficiency, continue to motivate considerations of modern blimps for surveillance missions.
Shape optimisation of blended-wing-body underwater gliders based on free-form deformation
Published in Ships and Offshore Structures, 2020
Jinglu Li, Peng Wang, Huachao Dong, Xumao Wu, Xu Chen, Caihua Chen
Many scholars have done excellent research work about BWBUG. D’Spain et al. (2007) studied the acoustic measurements of BWBUG. Wang et al. (2015) carried out design, analysis and performance prediction of BWBUG. Waldmann et al. (2016) studied a pneumatic variable buoyancy engine for BWBUG and enhanced the payload capacity. Wang et al. (2017) investigated a BWBUG’s hydrodynamic design optimisation with a surrogate model and achieved better hydrodynamic performance. Sun et al. (2015, 2017) studied a parametric geometric model and performed shape optimisation of BWBUG based on the model. The lift-drag ratio of BWBUG increased by 7%. Dong et al. (2018) performed a BWBUG’s shape optimisation by using Multi-surrogated-based differential evolution with multi-start exploration and the design performance got significantly improved.
Scientific rationale and conceptual design of a process-oriented shelfbreak observatory: the OOI Pioneer Array
Published in Journal of Operational Oceanography, 2020
Glen Gawarkiewicz, Albert J. Plueddemann
A novel element of the Pioneer Array design is the integration of mobile platforms (gliders and AUVs) with the moored array. Six Slocum gliders (Teledyne-Webb Research) were planned for deployment within the glider operations area (Figure 4). All of the glider hulls are rated to 1000 m depth. Four gliders outfitted with 1000 m buoyancy engines provide deep profiling over the continental slope. Two gliders are outfitted with a 200 m buoyancy engine to provide higher efficiency in shallow waters on the shelf. The six ‘track line following’ gliders measure the same 10 variables as the CPMs using 5 different instruments (Table 5). Instruments are usually operated during the dive only and, due to power constraints, the velocity profiler is typically operated every fourth dive. This may have implications for analysis of oxygen data on the gliders as, due to hysteresis effects, it is common practice to empirically regress lag coefficients to minimise differences between ascent and descent (e.g. Bittig et al., 2014). The instrumentation on the profiling gliders differs from that on the track-line gliders (Table 5) – the current profiler is replaced by a second fluorometer and a nitrate sensor.