scholarly journals Experimental investigation of the effect of a step and wedge on the performance of a high-speed craft in calm water and statistical analysis of its seakeeping in irregular waves

AIP Advances ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 095206
Author(s):  
Sayyed Mahdi Sajedi ◽  
Parviz Ghadimi
2017 ◽  
Author(s):  
Anne Fullerton ◽  
Charles Weil ◽  
Evan Lee ◽  
Minyee Jiang ◽  
Fredrick Stern ◽  
...  

Current structural design methods for high speed naval craft rely heavily on empirical methods. Though these methods have been employed reliably for a number of years, it is likely that an unknown level of conservatism exists in the prediction of impact loads. A better physical understanding of the dynamic response of high speed craft in seas would allow for increased structural optimization. The publicly releasable hull form Naval Surface Warfare Center Carderock Division (NSWCCD) Model 5365 (R/V Athena) was chosen to facilitate release of results to various computational teams. Model 5365 was tested in calm water, regular waves, and irregular waves. After reviewing data from the first test in 2014, it was determined that the model should be modified to enable towing from the longitudinal center of gravity. Model 5365 was then modified and re-tested using with added calm water speeds, and additional wave conditions. Calm water results from this test are presented with uncertainty analysis for resistance, heave, and trim.


Author(s):  
Christine M. Ikeda ◽  
Carolyn Q. Judge

High–speed planing boats are subject to repeated slamming impacts, which can cause structural damage and discomfort or injury to passengers. The goal of this research is to study the fundamental physics of the water-impact of high–speed planing hulls and to measure the slamming loads and resulting motions of the craft upon re–entry into the water after becoming partially airborne. A set of towed scale–model experiments was conducted in calm water, regular waves and irregular waves to capture a sequence of individual impact events. Pressure measurements were taken on the bottom of the hull using both point sensors (PCB Piezotronics) and a pressure mapping system (Tekscan). The pressure signals from the pressure pads (providing both spatial and temporal resolution) and the point–pressure measurements (high temporal resolution) will be presented for individual slam events, allowing a deterministic approach to investigating high–speed planing craft wave slamming.


2012 ◽  
Vol 43 (4) ◽  
pp. 481-496 ◽  
Author(s):  
Valeriy Ivanovich Zapryagaev ◽  
Nikolay Petrovich Kiselev ◽  
Dmitriy Andreevich Gubanov

2013 ◽  
Vol 420 ◽  
pp. 47-50
Author(s):  
Ying Yang ◽  
Jing Hua Dai

Under high and super-high speed, oil film of the journal bearing is easy to crack and then becomes cavitation. The existence of cavitation has an important effect on the work characteristics of the shaft. On the journal bearing experiment rig the cavitation characteristics of the three-groove journal beaing were studied. The influences of the shaft rotating speed and supply pressure on cavitation shape were investigated. The results show that rotating speed and supply pressure have a clear effect on the cavitation shape, and the number of cavitation strip in the rupture zone decreases when the supply pressure increases.


2015 ◽  
Vol 105 (05) ◽  
pp. 285-290
Author(s):  
C. Brecher ◽  
M. Fey ◽  
J. Falker

Das Floating-Roller-Ball (FRB)-Lager ist ein Konzept für Radiallager als Loslager für Hochgeschwindigkeits-Motorspindeln, das die Vorteile von Zylinderrollenlagern und angestellten Mehrpunktlagern in einer neuen Wälzkörpergeometrie kombiniert. Zur Auslegung des ersten Prototyps wurde mithilfe eines Berechnungstools das theoretische Betriebsverhalten untersucht. Die Berechnungsergebnisse liefern Randbedingungen als Grundlage zur experimentellen Untersuchung des Lagerkonzepts.   Floating roller ball bearings provide a new floating bearing system for high-speed motor spindles, combining the advantages of both cylindrical roller bearings and elastically mounted multi-contact point bearings in a new roller geometry. To design the first prototype, the operational behavior of the bearing system was analyzed theoretically by a new calculation tool. The results provide the basis for the experimental investigation of the bearing concept.


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