The Effect of Water Depth on the Predatory Behavior of the Water Stick Insect, Ranatra-Dispar (Heteroptera, Nepidae)

1987 ◽  
Vol 35 (5) ◽  
pp. 443 ◽  
Author(s):  
PCE Bailey
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Prey Density ◽  
Vertical Component ◽  
Stick Insect ◽  
Predatory Behavior ◽  
Sensory Organs ◽  
Capture Success ◽  
Effect Of Water

The effect of water depth and prey density on the capture success (as measured by the number of prey eaten) of the aquatic, sit-and-wait predator, Ranatra dispar, was examined in the laboratory. When water depth was held constant at 5, 10, 20 or 30 cm, prey densities of 10, 15, 30 or 40 prey per container had no effect at the two shallowest depths, where very few prey were caught or eaten at any density. At 20 and 30 cm, density had a significant effect with progressively more prey being consumed as density increased. When prey density was held constant at 1, 2, 4 or 8 prey per litre, water depth significantly affected the proportion of prey eaten. At each density, predators held in 5 cm of water and, to some extent, those in 10 cm consumed significantly fewer prey than those in 20 or 30 cm. It is suggested that fewer prey are caught in shallow water because: (1) the predator cannot put itself in the position which most favours an efficient strike; (2) the absence of a significant 'vertical' component in the environment reduces the effectiveness of the sensory organs in locating prey. The lower capture success in shallow water may cause adult R. dispar to avoid shallow water, thus providing a partial refuge in which small R. dispar can avoid competing with adults for prey of similar sizes.

Effect of Water Depth on Nitrogen Use Efficiency and Nitrogen‐15 Balance in Lowland Rice 1

1987 ◽  
Vol 79 (2) ◽  
pp. 210-216 ◽  
Author(s):  
S. K. De Datta ◽  
W. N. Obcemea ◽  
R. Y. Chen ◽  
J. C. Calabio ◽  
R. C. Evangelista
Keyword(s):  
Water Depth ◽  
Nitrogen Use Efficiency ◽  
Lowland Rice ◽  
Nitrogen Use ◽  
Effect Of Water ◽  
Use Efficiency

Resistance Tests of an Articulated Pusher Barge System in Deep and Shallow Water

2021 ◽  
Author(s):  
Li Zhang ◽  
Lei Xing ◽  
Mingyu Dong ◽  
Weimin Chen
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Deep Water ◽  
Water Resistance ◽  
Model Tests ◽  
System 2 ◽  
Changing Trend ◽  
The Difference ◽  
Transport Vessel ◽  
Resistance Performance

Abstract Articulated pusher barge vessel is a short-distance transport vessel with good economic performance and practicability, which is widely used in the Yangtze River of China. In this present work, the resistance performance of articulated pusher barge vessel in deep water and shallow water was studied by model tests in the towing tank and basin of Shanghai Ship and Shipping Research Institute. During the experimental investigation, the articulated pusher barge vessel was divided into three parts: the pusher, the barge and the articulated pusher barge system. Firstly, the deep water resistance performance of the articulated pusher barge system, barge and the pusher at design draught T was studied, then the water depth h was adjusted, and the shallow water resistance at h/T = 2.0, 1.5 and 1.2 was tested and studied respectively, and the difference between deep water resistance and shallow water resistance at design draught were compared. The results of model tests and analysis show that: 1) in the study of deep water resistance, the total resistance of the barge was larger than that of the articulated pusher barge system. 2) for the barge, the shallow water resistance increases about 0.4–0.7 times at h/T = 2.0, 0.5–1.1 times at h/T = 1.5, and 0.7–2.3 times at h/T = 1.2. 3) for the pusher, the shallow water resistance increases about 1.0–0.4 times at h/T = 2.7, 1.2–0.9 times at h/T = 2.0, and 1.7–2.4 times at h/T = 1.6. 4) for the articulated pusher barge system, the shallow water resistance increases about 0.2–0.3 times at h/T = 2.0, 0.5–1.3 times at h/T = 1.5, and 1.0–3.5 times at h/T = 1.2. Furthermore, the water depth Froude number Frh in shallow water was compared with the changing trend of resistance in shallow water.

Stability of offshore structures in shallow water depth

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
Structural Response ◽  
Offshore Structures ◽  
Exploration And Production ◽  
Subsea Pipelines ◽  
Wave Induced ◽  
Shallow Water Depth

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.

Experimental Investigation of Trimaran Models in Shallow Water

2014 ◽  
Vol 30 (02) ◽  
pp. 66-78
Author(s):  
Mark Pavkov ◽  
Morabito Morabitob
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Critical Speed ◽  
Water Effect ◽  
Finite Water Depth ◽  
Speed Regime ◽  
Displacement Speed ◽  
Littoral Combat Ship ◽  
Shallow Water Effect ◽  
The U.S

Experiments were conducted at the U.S. Naval Academy's Hydromechanics Laboratory to determine the effect of finite water depth on the resistance, heave, and trim of two different trimaran models. The models were tested at the same length to water depth ratios over a range of Froude numbers in the displacement speed regime. The models were also towed in deep water for comparison. Additionally, the side hulls were adjusted to two different longitudinal positions to investigate possible differences resulting from position. Near critical speed, a large increase in resistance and sinkage was observed, consistent with observations of conventional displacement hulls. The data from the two models are scaled up to a notional 125-m length to illustrate the effects that would be observed for actual ships similar in size to the U.S. Navy's Independence Class Littoral Combat Ship. Faired plots are developed to allow for rapid estimation of shallow water effect on trimaran resistance and under keel clearance. An example is provided.

scholarly journals Effect of water depth on the growth dynamics of Phragmites australis.

2001 ◽  
pp. 141-150
Author(s):  
Norio TANAKA ◽  
Takashi ASAEDA ◽  
Katsutoshi TANIMOTO ◽  
Shiromi KARUNARATNE
Keyword(s):  
Phragmites Australis ◽  
Water Depth ◽  
Growth Dynamics ◽  
Effect Of Water

Effect of water depth on a novel absorber plate of pyramid solar still coated with TiO2 nano black paint

2019 ◽  
Vol 213 ◽  
pp. 185-191 ◽  
Author(s):  
A.E. Kabeel ◽  
Ravishankar Sathyamurthy ◽  
Swellam W. Sharshir ◽  
A. Muthumanokar ◽  
Hitesh Panchal ◽  
...  
Keyword(s):  
Water Depth ◽  
Solar Still ◽  
Absorber Plate ◽  
Black Paint ◽  
Effect Of Water

scholarly journals ADDED MASSES OF LARGE TANKERS BERTHING TO DOLPHINS

1976 ◽  
Vol 1 (15) ◽  
pp. 161 ◽  
Author(s):  
Taizo Hayashi ◽  
Masujiro Shirai
Keyword(s):  
Shallow Water ◽  
Froude Number ◽  
Water Depth ◽  
Head Loss ◽  
Theoretical Formula ◽  
Counter Flow ◽  
Added Masses ◽  
Mass Factor ◽  
Large Vessels ◽  
Good Agreement

The added masses of large tankers berthing to dolphins are studied both theoretically and experimentally. The movements of large vessels in shallow water in the directions normal to their planes of symmetry cause counterflows of appreciable velocities under the hulls. The inertia of these counter-flows is shown to have an important effect on the added masses of the vessels. A theoretical formula is derived to determine the mass factor of an ocean vessel in shallow water as a function of the ratio Draught/Water- depth, the Froude number of the vessel and the coefficient of head loss of the counter-flow under the hull. Experiment is made to determine the mass factor. Comparison:, between the theory and the experiment shows a good agreement.

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