Hydroplaning by ducklings: overcoming limitations to swimming at the water surface

1995 ◽  
Vol 198 (7) ◽  
pp. 1567-1574 ◽  
Author(s):  
T Aigeldinger ◽  
F Fish
Keyword(s):  
Swimming Speed ◽  
Kinematic Analysis ◽  
Water Surface ◽  
Escape Behavior ◽  
Anas Platyrhynchos ◽  
The Body ◽  
Maximum Speed ◽  
Stroke Frequency ◽  
Low Speed ◽  
Burst Swimming

Rapid escape behavior by mallard (Anas platyrhynchos) ducklings is restricted to burst swimming at the water surface. Maximum speed may be limited because of the pattern of waves created as the duckling's body moves through the water (hull speed). Burst speeds for 9-day-old ducklings were compared with predicted hull speeds, based on the waterline length of ducklings either resting in water or actively swimming. Kinematic analysis of video tapes showed a mean maximum burst speed of 1.73 m s-1, which was four times greater than the predicted hull speed. At burst velocities, stroke frequency was 1.9 times higher than the stroke frequency measured during steady low-speed paddling. Transition to burst speeds from steady paddling occurred near predicted hull speed. The paddling motions of the webbed feet were used to generate both thrust and lift. By using lift to raise the body above the water surface, the influence of waves in restricting maximum swimming speed is negated. The duckling's body becomes a planing type of hull and skims on the water surface.

scholarly journals Swimming Performance of Four Carps on the Yangtze River for Fish Passage Design

2021 ◽  
Vol 13 (3) ◽  
pp. 1575
Author(s):  
Junjun Tan ◽  
Hong Li ◽  
Wentao Guo ◽  
Honglin Tan ◽  
Senfan Ke ◽  
...  
Keyword(s):  
Body Length ◽  
Swimming Speed ◽  
Swimming Performance ◽  
Fish Habitat ◽  
Silver Carp ◽  
Fish Passage ◽  
The Body ◽  
Bighead Carp ◽  
Black Carp ◽  
Burst Swimming

Anthropogenic engineered structures alter the local ecological connectivity of river and survival habitat of native fishes. The swimming performance is critical for establishing fish passage or fish habitat. This study evaluated the swimming performance of four carps (black carp, grass carp, silver carp and bighead carp) with smaller body lengths (1.0–9.0 cm) in a swimming flume. The results showed that the critical and burst swimming speed (m/s) of the four carps increased with the increased body length, and the relative (critical and burst) swimming speed (the critical and burst swimming speed divided by the body length, BL/s) decreases with body length. The critical and burst swimming speed of each species at two individual length groups (1.0–5.0 cm, 5.1–9.0 cm) was significantly different (p < 0.05), and the water velocities in fish passage should be less than the fish burst swimming speed. The results further provided the swimming performance data of juvenile carps and provided technical reference for the construction of fish passage and the restoration of ecological habitat.

scholarly journals Influence of tail shape on tadpole swimming performance

2000 ◽  
Vol 203 (14) ◽  
pp. 2149-2158 ◽  
Author(s):  
J. Van Buskirk ◽  
S.A. McCollum
Keyword(s):  
Swimming Performance ◽  
Tail Length ◽  
The Body ◽  
Maximum Speed ◽  
Escape Time ◽  
Hyla Versicolor ◽  
Naturally Occurring ◽  
Tail Shape ◽  
Burst Swimming ◽  
Insect Predators

Many tadpoles respond to insect predators by developing deeper, and sometimes longer, tails. It has been assumed that the larger tail enhances aspects of swimming performance, because deep-tailed tadpoles survive well when confronted with hunting predators. We tested this hypothesis using both naturally occurring and surgically created variation in tail morphology of Hyla versicolor tadpoles. We measured swimming performance (maximum speed, time to reach a 2.5 cm radius, and angle of escape) and morphology (size and shape of the body and tail) in 288 tadpoles, of which half possessed the predator-induced morphology and the other half were from predator-free ponds. Large tadpoles swam faster than small ones, and shape was significantly correlated with size-corrected swimming performance. The fastest tadpoles had relatively shallow bodies and tail fins, and short tails; there was no difference in swimming performance between predator-induced and no-predator tadpoles. We performed an experiment to create independent variation in tail depth and length by surgically manipulating tail shape in 270 tadpoles. Three tail-length treatments reduced the length of the tail fin by 21 %, 34 % and 55 %; three tail-depth treatments reduced the maximum depth of the tail fin by 11 %, 34 % and 59 %; two additional treatments controlled for the effects of anaesthesia and surgery. The angle of escape was unaffected by surgery. Maximum speed and minimum escape time were both significantly impaired by the high-removal treatments, but showed no evidence of decline until 30 % of the tail (length or depth) was removed. These results suggest that the relatively deep tails in predator-induced tadpoles (approximately 10 % deeper than in no-predator tadpoles) do not improve performance in burst swimming. Thus, predator-induced tadpoles are less vulnerable to predation for reasons other than enhanced swimming performance.

Direct Kinematic Analysis of a Hexapod Spider-Like Mobile Robot

2011 ◽  
Vol 403-408 ◽  
pp. 5053-5060 ◽  
Author(s):  
Mostafa Ghayour ◽  
Amir Zareei
Keyword(s):  
Angular Velocity ◽  
Mobile Robot ◽  
Time Variation ◽  
Kinematic Analysis ◽  
The Body ◽  
Specific Time ◽  
Centre Of Gravity ◽  
Joint Variable ◽  
Direct Kinematics ◽  
Robot Platform

In this paper, an appropriate mechanism for a hexapod spider-like mobile robot is introduced. Then regarding the motion of this kind of robot which is inspired from insects, direct kinematics of position and velocity of the centre of gravity (C.G.) of the body and noncontact legs are analysed. By planning and supposing a specific time variation for each joint variable, location and velocity of the C.G. of the robot platform and angular velocity of the body are obtained and the results are shown and analysed.

Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size

1996 ◽  
Vol 199 (10) ◽  
pp. 2235-2242 ◽  
Author(s):  
E Drucker ◽  
J Jensen
Keyword(s):  
Body Size ◽  
Swimming Speed ◽  
Beat Frequency ◽  
Limited Range ◽  
The Body ◽  
Small Fish ◽  
Large Fish ◽  
Pectoral Fin ◽  
Transition Speed ◽  
Speed Up

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.35&shy;0.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoral&shy;caudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent.

Kinematics and efficiency of steady swimming in adult axolotls (Ambystoma mexicanum)

1997 ◽  
Vol 200 (13) ◽  
pp. 1863-1871 ◽  
Author(s):  
K D'Août ◽  
P Aerts
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Natural Habitat ◽  
Total Body Length ◽  
Ambystoma Mexicanum ◽  
The Body ◽  
Entire Body ◽  
Amplitude Profile ◽  
Wide Range ◽  
Tail Tip

The kinematics of steady swimming at a wide range of velocities was analysed using high-speed video recordings (500 frames s-1) of eight individuals of Ambystoma mexicanum swimming through a tunnel containing stationary water. Animals in the observed size range (0.135&shy;0.238 m total body length) prefer to swim at similar absolute speeds, irrespective of their body size. The swimming mechanism is of the anguilliform type. The measured kinematic variables &shy; the speed, length, frequency and amplitude (along the entire body) of the propulsive wave &shy; are more similar to those of anguilliform swimming fish than to those of tadpoles, in spite of common morphological features with the latter, such as limbs, external gills and a tapering tail. The swimming speed for a given animal size correlates linearly with the tailbeat frequency (r2=0.71), whereas the wavelength and tail-tip amplitude do not correlate with this variable. The shape of the amplitude profile along the body, however, is very variable between the different swimming bouts, even at similar speeds. It is suggested that, for a given frequency, the amplitude profile along the body is adjusted in a variable way to yield the resulting swimming speed rather than maintaining a fixed-amplitude profile. The swimming efficiency was estimated by calculating two kinematic variables (the stride length and the propeller efficiency) and by applying two hydrodynamic theories, the elongated-body theory and an extension of this theory accounting for the slope at the tail tip. The latter theory was found to be the most appropriate for the axolotl's swimming mode and yields a hydromechanical efficiency of 0.75&plusmn;0.04 (mean &plusmn; s.d.), indicating that Ambystoma mexicanum swims less efficiently than do anuran tadpoles and most fishes. This can be understood given its natural habitat in vegetation at the bottom of lakes, which would favour manoeuvrability and fast escape.

Surface Gravity Waves

2017 ◽  
Author(s):  
John A. Adam
Keyword(s):  
Gravity Waves ◽  
Water Waves ◽  
Water Surface ◽  
Wave Pattern ◽  
The Body ◽  
Surface Gravity ◽  
Shallow Water Waves ◽  
Ship Waves ◽  
Surface Gravity Waves ◽  
Basic Fluid

This chapter deals with the underlying mathematics of surface gravity waves, defined as gravity waves observed on an air–sea interface of the ocean. Surface gravity waves, or surface waves, differ from internal waves, gravity waves that occur within the body of the water (such as between parts of different densities). Examples of gravity waves are wind-generated waves on the water surface, as well tsunamis and ocean tides. Wind-generated gravity waves on the free surface of the Earth's seas, oceans, ponds, and lakes have a period of between 0.3 and 30 seconds. The chapter first describes the basic fluid equations before discussing the dispersion relations, with a particular focus on deep water waves, shallow water waves, and wavepackets. It also considers ship waves and how dispersion affects the wave pattern produced by a moving object, along with long and short waves.

A Study of Water Surface Deformation Due to Tip Vortices Wing-in-Ground Effect

2007 ◽  
Vol 51 (02) ◽  
pp. 182-186
Author(s):  
Tracie J. Barber
Keyword(s):  
Water Surface ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Ground Effect ◽  
Aerodynamic Performance ◽  
The Body ◽  
Vehicle Design ◽  
Two Dimensional ◽  
Tip Vortices ◽  
Wing Tip

The accurate prediction of ground effect aerodynamics is an important aspect of wing-in-ground (WIG) effect vehicle design. When WIG vehicles operate over water, the deformation of the nonrigid surface beneath the body may affect the aerodynamic performance of the craft. The likely surface deformation has been considered from a theoretical and numerical position. Both two-dimensional and three-dimensional cases have been considered, and results show that any deformation occurring on the water surface is likely to be caused by the wing tip vortices rather than an increased pressure distribution beneath the wing.

Mechanics of the fast-start: muscle function and the role of intramuscular pressure in the escape behavior of amia calva and polypterus palmas

1998 ◽  
Vol 201 (22) ◽  
pp. 3041-3055 ◽  
Author(s):  
MW Westneat ◽  
ME Hale ◽  
MJ Mchenry ◽  
JH Long
Keyword(s):  
Muscle Activity ◽  
Escape Response ◽  
Muscle Force ◽  
Escape Behavior ◽  
Pressure Change ◽  
The Body ◽  
Intramuscular Pressure ◽  
Fast Start ◽  
Amia Calva

The fast-start escape response is a rapid, powerful body motion used to generate high accelerations of the body in virtually all fishes. Although the neurobiology and behavior of the fast-start are often studied, the patterns of muscle activity and muscle force production during escape are less well understood. We studied the fast-starts of two basal actinopterygian fishes (Amia calva and Polypterus palmas) to investigate the functional morphology of the fast-start and the role of intramuscular pressure (IMP) in escape behavior. Our goals were to determine whether IMP increases during fast starts, to look for associations between muscle activity and elevated IMP, and to determine the functional role of IMP in the mechanics of the escape response. We simultaneously recorded the kinematics, muscle activity patterns and IMP of four A. calva and three P. palmas during the escape response. Both species generated high IMPs of up to 90 kPa (nearly 1 atmosphere) above ambient during the fast-start. The two species showed similar pressure magnitudes but had significantly different motor patterns and escape performance. Stage 1 of the fast-start was generated by simultaneous contraction of locomotor muscle on both sides of the body, although electromyogram amplitudes on the contralateral (convex) side of the fish were significantly lower than on the ipsilateral (concave) side. Simultaneous recordings of IMP, escape motion and muscle activity suggest that pressure change is caused by the contraction and radial swelling of cone-shaped myomeres. We develop a model of IMP production that incorporates myomere geometry, the concept of constant-volume muscular hydrostats, the relationship between fiber angle and muscle force, and the forces that muscle fibers produce. The timing profile of pressure change, behavior and muscle action indicates that elevated muscle pressure is a mechanism of stiffening the body and functions in force transmission during the escape response.

scholarly journals The wave making resistance prediction of a mini-submarine by using tent function method

2018 ◽  
Vol 177 ◽  
pp. 01003 ◽  
Author(s):  
Aries Sulisetyono ◽  
Ardi Nugroho Yulianto
Keyword(s):  
Water Surface ◽  
Function Method ◽  
The Body ◽  
Source Distribution ◽  
Hull Form ◽  
Operational Conditions ◽  
A Value ◽  
Resistance Prediction ◽  
Havelock Source ◽  
Good Agreement

This paper describes the wave making resistance solution of a mini submarine operating in under water surface with different level depth. The Thin ship theory was adopted to solve the problem for a case of the slenderness body. The source distribution along the centre plane of the body was expressed in Green’s function of Havelock source potential under water surface. The Tent function method was proposed to illustrate the hull form based on offsets data, and to solve the Michell integral problem numerically. Four operational conditions were performed i.e. floating, snorkelling, and diving with 0.5m and 1m under water surface. The computational results for the mini submarine with length of 2m and diameter of 0.25m explained a more deeply operated under water surface cause to decrease a value of wave making resistance for all cases of Froude numbers. While in the diving conditions of 0.5m and 0.1m under the water surface, the wave making resistance were resulted about 64% and 74% less than the case of floating condition respectively. Furthermore, the effect of vertical fin on the body was investigated, where the wave making resistance could increase average 7.2% in snorkelling, 11.4% in 0.5m diving, and in the 1m diving about 9.07% for all Froude numbers. Over all the results of this approach shown a good agreement with the results come from Mitchell code.

The role of the nasal glands in the survival of ducks (Anas platyrhynchos) exposed to hypertonic saline drinking water

1972 ◽  
Vol 50 (5) ◽  
pp. 611-617 ◽  
Author(s):  
E. L. Bradley ◽  
W. N. Holmes
Keyword(s):  
Drinking Water ◽  
Body Weight ◽  
Water Balance ◽  
Hypertonic Saline ◽  
Anas Platyrhynchos ◽  
Active Material ◽  
Plasma Concentrations ◽  
Plasma Osmolality ◽  
The Body ◽  
Nasal Glands

The supraorbital nasal glands were removed from the duck (Anas platyrhynchos) 1 week before experimentation. When sham-operated birds were given hypertonic saline drinking water (282 mM NaCl, 6 mM KCl) for 70 h they maintained their body weights and remained in positive water balance. When the ducks lacking nasal glands were similarly treated they became severely dehydrated, lost body weight at the rate of 5.59 ± 1.1 g/h and showed significant increases in the plasma concentrations of Na+, Cl−, K+, and total osmotically active material. When the glandless birds were given hypertonic saline drinking water, the disparity between the measured plasma osmolality and the osmolality calculated on the basis of the Na+, Cl−, and K+ concentrations in plasma increased two-fold. No such change in disparity between the measured and calculated osmolalities of plasma in the sham-operated birds was observed. Forty-eight hours after their return to a diet containing fresh drinking water, the birds without nasal glands regained some of the body weight they had lost and the plasma electrolyte concentrations were restored towards normal. It is concluded that in the absence of nasal glands, the kidney alone is incapable of maintaining positive water balance in ducks fed hypertonic saline as their only source of drinking water.

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