Simulation of a ship operating in an open-water ice channel

Modern ice breakers, using new technology, are now able to create channels through level ice and clean out the ice fragments, resulting in an open-water channel between two large ice sheets. Whilst this negates the potential resistance increase on a following vessel due to interacting with the broken ice pieces, the ship performance will still be influenced by the two large ice sheets on either side. The effect of such ice sheets on ships has to date not been studied in detail, so the channel effect is usually ignored during ship design processes and power estimates. The present paper reports on work to develop a computational model to simulate a ship advancing in an open-water ice channel and investigate the associated ship-wave-ice interaction. Based on a series of simulations, this work how the ship resistance and wake change with ship speed, channel width and ice thickness

Numerical analysis of shipping water impacting a step structure

Shipping water, the flow washing over and impacting the upper decks of ships and offshore structures, occurs frequently during their service life and often causes structural problems. For engineers to design safe floating structures subjected to shipping water it is essential to gain an in-depth understanding of its depth and flow field, and the resulting impact forces. In this work, Computational Fluid Dynamics (CFD) is applied to understand the physics of shipping water washing over a stepped platform. We find that the most accurate solutions are obtained with the turbulence closure. The hydrodynamic load generated by the shipping water is found to strongly depends on the kinematic energy of the water hitting the step. It is shown that with smaller values of the freeboard a more dynamic flow ensues, with a stronger vortex and larger velocity gradient resulting in deeper shipping water and a larger impact force

A Systematic Review on Curcumin and Anti-Plasmodium berghei Effects

BACKGROUND: Turmeric (Curcuma longa L.) is a popular spice containing curcumin that is responsible for its therapeutic effects. Curcumin with anti-inflammatory, antioxidant, anti-cancer, and antimicrobial activities has led to a lot of research focusing on it over the years. This systematic review aimed to evaluate research on the anti-Plasmodium berghei activity of curcumin and its derivatives. METHODS: Our study was performed according to PRISMA guidelines and was recorded in the database of a systematic review and preclinical meta-analysis of CAMARADESNC3Rs (SyRF). The search was performed in five databases, namely Scopus, PubMed, Web of Science, EMBASE, and Google Scholar, from 2010 to 2020. The following keywords were searched: "Plasmodium berghei", "Medicinal Plants", "Curcumin", "Concentration", Animals kind", "Treatment Durations", "Routes of Administration" and "in vivo". RESULTS: Of the 3,500 papers initially obtained, 14 articles were reliable and were thus scrutinized. Animal models were included in all studies. The most commonly used animal strain was Albino (43), followed by C57BL/6 (22). The other studies used various murine strains, including BALB/c (14) and ICR (7). Two (14) studies did not mention the strain of animal model used. Curcumin alone or in combination with other compounds depending on the dose used, route of administration, and animal model showed a moderate to strong anti-Plasmodium berghei effect. CONCLUSION: According to the studies, curcumin has anti-malarial effects on Plasmodium berghei, and, however, its effect on human Plasmodium is unclear. Due to the side effects and drug resistance of current drugs in the treatment of human malaria, the use of new compounds with few or no side effects, such as curcumin, is recommended as an alternative or complementary treatment. Copyright© Bentham Science Publishers; For any queries, please email at [email protected]

Letter: Hydroelastic interactions between water waves and floating freshwater ice

Hydroelastic interactions between regular water waves and floating freshwater ice are investigated using laboratory experiments for a range of incident wave periods and steepnesses. It is shown that only incident waves with sufficiently long period and large steepness break up the ice cover and that the extent of breakup increases with increasing period and steepness. Furthermore, it is shown that an increasing proportion of the incident wave propagates through the ice-covered water as the period and steepness increase, indicating the existence of a positive feedback loop between the ice breakup and increased wave propagation

Numerical analysis of shipping water impacting a step structure

Shipping water, the flow washing over and impacting the upper decks of ships and offshore structures, occurs frequently during their service life and often causes structural problems. For engineers to design safe floating structures subjected to shipping water it is essential to gain an in-depth understanding of its depth and flow field, and the resulting impact forces. In this work, Computational Fluid Dynamics (CFD) is applied to understand the physics of shipping water washing over a stepped platform. We find that the most accurate solutions are obtained with the k−ε turbulence closure. The hydrodynamic load generated by the shipping water is found to strongly depends on the kinematic energy of the water hitting the step. It is shown that with smaller values of the freeboard a more dynamic flow ensues, with a stronger vortex and larger velocity gradient resulting in deeper shipping water and a larger impact force.QC 20220318</p

Wave attenuation due to ice cover:An experimental model in a wave-ice flume

Waves penetrate deep into the ice covered seas, inducing breakup of the ice cover. Concomitantly, the ice cover attenuates the wave energy over distance, so that wave impacts die out eventually. Observations of wave attenuation and concurrent wave-induced breakup in the literature are serendipitous due to difficulties in making measurements in ice covered seas. Hence understanding of wave-ice interactions remain uncertain. Here we present measurements of wave propagation through ice covered waters in the new experimental wave-ice facility at the University of Melbourne. The facility comprises of a 14m long and 0.76m wide flume in a refrigerated chamber, where temperatures can be lowered down to-12 degrees Celsius to generate a continuous ice cover on the water surface. A wave maker, installed at one end, is used to generate regular waves, ranging from gently-sloping to storm-like conditions. Wave attenuation rates are determined from video-camera images of the displacements of markers embedded in the ice cover. The experiments investigated wave propagation through the continuous ice cover, breakup, and propagation through the broken ice cover. Spatial evolution of the breakup and geometrical properties of floes are monitored and correlated with incident wave properties. Wave attenuation over broken ice is investigated and compared against the continuous ice case