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Will humans swim faster or slower in syrup?
Aiche Journal
Abstract
The scientific and engineering principles that underlie chemical engineering can also be used to understand a wide variety of other phenomena, including in areas not thought of as being central to our profession. As such applications might be of interest to our readers, we will consider brief submissions for publication in this category as R&D notes. These submissions will undergo review, and novelty will be an important factor in reaching an editorial decision.
The first such article, “Will Humans Swim Faster or Slower in Syrup?” by Brian Gettelfinger and associate editor Ed Cussler, appears in this issue. Stanley I. Sandler Editor
... From the seminal work of Counsilman (1968) to the present, much of swimming research has been done through careful observation by practitioners and experts in the sport. There are works focused on the biomechanics of swimming, including Miller (1975), Clarys (1978), Hay (1988), Kolmogorov et al. (1997), Toussaint et al. (2000), Gettelfinger &Cussler (2004), andPolidori et al. (2006). There are also physiologically focused studies, such as Faulkner (1968), Magel (1971), Holmér (1972), and Troup (1999). ...
... From the seminal work of Counsilman (1968) to the present, much of swimming research has been done through careful observation by practitioners and experts in the sport. There are works focused on the biomechanics of swimming, including Miller (1975), Clarys (1978), Hay (1988), Kolmogorov et al. (1997), Toussaint et al. (2000), Gettelfinger &Cussler (2004), andPolidori et al. (2006). There are also physiologically focused studies, such as Faulkner (1968), Magel (1971), Holmér (1972), and Troup (1999). ...
... As an interesting aside, Gettelfinger & Cussler (2004) provided a singularly unique study with the sole objective to determine if a swimmer would swim any faster in a fluid more viscous than water. This study drew quite a bit of attention in the swimming world and in the popular media, perhaps because one of the authors was an elite swimmer (Gettelfinger swam in the 2004 US Olympic Trials) and because the work was done in an Olympic year. ...
Nowhere in sport is performance so dependent on the interaction of the athlete with the surrounding medium than in competitive swimming. As a result, understanding (at least implicitly) and controlling (explicitly) the fluid dynamics of swimming are essential to earning a spot on the medal stand. This is an extremely complex, highly multidisciplinary problem with a broad spectrum of research approaches. This review attempts to provide a historical framework for the fluid dynamics-related aspects of human swimming research, principally conducted roughly over the past five decades, with an emphasis on the past 25 years. The literature is organized below to show a continuous integration of computational and experimental technologies into the sport. Illustrations from the authors' collaborations over a 10-year period, coupling the knowledge and experience of an elite-level coach, a lead biomechanician at USA Swimming, and an experimental fluid dynamicist, are intended to bring relevance and immediacy to the review.
... The effect of fluid viscosity on swimming speed was already debated by Newton and Huygens [10], but is still puzzling. In a famous experiment Gettelfinger and Cussler [8] compared the speed of human swimmers in a pool filled with syrup with their performance in a pool filled with water. The viscosity and mass density of the syrup were twice as high as that of water. ...
... Here we discuss the syrup question [8], [10] in the full range of parameters on the basis of hydromechanical models, a combination of classical mechanics and hydrodynamics [13], [4]. We conjecture that with a proper choice of hydrodynamic interactions a hydromechanical model can provide a realistic picture of a swimming body, even for high Reynolds number. ...
... The density of molasses is ρ = 1600 kg m −3 and the dynamic viscosity of molasses µ varies between 5 and 10 Pa s, so we will take µ = 7.5 Pa s. Gettelfinger and Cussler suggest that a human swimmer with height 1.8 m should have a frontal area of 0.1 m 2 , which would give a characteristic length scale L = (0.1 m 2 ) 1/2 [7]. We will assume that a person swimming in molasses would move forward with a speed of around 1.5 mph, which gives U = 0.67 ms −1 . ...
On the 15th January 1919, a storage container filled with molasses in the North End of Boston burst open, possibly because of thermal expansion of the liquid inside. In a scene which one might imagine in a macabre fairy tale, a 7 metre high wave of sweet-smelling molasses left the container and swept through the surrounding neighbourhood, killing 21 civilians and injuring another 150. Half of the casualties were due to being crushed or drowned, with the other half being due to injuries or infection [1]. The event came to be known as the Great Molasses Flood. In Section 1, we discuss the claim that many casualties occurred because people were unable to move in the syrup. We argue that this is plausible due to the scallop theorem. In Section 2, we discuss the impact force due to a non-Newtonian fluid colliding with a solid body. In Section 3, we estimate the speed of the wave and find it was probably lower than the one reported in many popular accounts. We also give a simple argument explaining why the container collapsed. We conclude in Section 4 and observe that our findings might also be relevant for more common phenomena which can occur in the natural world.
... The density of molasses is ρ = 1600 kg m −3 and the dynamic viscosity of molasses µ varies between 5 and 10 Pa s, so we will take µ = 7.5 Pa s. Gettelfinger and Cussler suggest that a human swimmer with height 1.8 m should have a frontal area of 0.1 m 2 , which would give a characteristic length scale L = (0.1 m 2 ) 1/2 [7]. We will assume that a person swimming in molasses would move forward with a speed of around 1.5 mph, which gives U = 0.67 ms −1 . ...
On the 15th January 1919, a storage container filled with molasses in the North End of Boston burst open, possibly because of thermal expansion of the liquid inside. In a scene which one might imagine in a macabre fairy tale, a 7 metre high wave of sweet-smelling molasses left the container and swept through the surrounding neighbourhood, killing 21 civilians and injuring another 150. Half of the casualties were due to being crushed or drowned, with the other half being due to injuries or infection [1]. The event came to be known as the Great Molasses Flood. In Section 1, we discuss the claim that many casualties occurred because people were unable to move in the syrup. We argue that this is plausible due to the scallop theorem. In Section 2, we discuss the impact force due to a non-Newtonian fluid colliding with a solid body. In Section 3, we estimate the speed of the wave and find it was probably lower than the one reported in many popular accounts. We also give a simple argument explaining why the container collapsed. We conclude in Section 4 and observe that our findings might also be relevant for more common phenomena which can occur in the natural world.
... Here, we discuss the syrup question 8,10 in the full range of parameters on the basis of hydromechanical models, a combination of classical mechanics and hydrodynamics. 4,13 We conjecture that with a proper choice of hydrodynamic interactions a hydromechanical model can provide a realistic picture of a swimming body, even for high Reynolds number. ...
The swimming of a dumbbell and of a three-sphere chain in a viscous incompressible fluid is studied on the basis of simplified equations of motion, which take into account both friction and inertial effects. The study is focused on the question of whether a particular swimmer will swim slower or faster in syrup than in water. The answer to this question for the dumbbell turns out to be complex. For the three-sphere chain, there is a small increase in swimming velocity in syrup.
... It was almost twenty years ago that researchers of the University of Minnesota attempted to answer the famous question about whether humans would swim slower in syrup than in water. [1] Intuitively, one might think that swimming in a pool of a substance twice as viscous as water would slow down a recreational swimmer. Surprisingly, they demonstrated that it does not. ...
Although many biological fluids like blood and mucus exhibit high viscosities, there are still many open questions concerning the swimming behavior of microswimmers in highly viscous media, limiting research to idealized laboratory conditions instead of application‐oriented scenarios. Here, we analyze the effect of viscosity on the swimming speed and motion pattern of four kinds of microswimmers of different sizes which move by contrasting propulsion mechanisms: two biological swimmers (bovine sperm cells and Bacillus subtilis bacteria) which move by different bending patterns of their flagellaand two artificial swimmers with catalytic propulsion mechanisms (alginate microtubes and Janus Pt@SiO 2 spherical microparticles). Experiments consider two different media (glycerol and methylcellulose) with increasing viscosity, but also the impact of surface tension, catalyst activity and diffusion coefficients are discussed and evaluated.
... On the one hand, increased viscosity increases drag on the swimming object; but this increased viscosity simultaneously gives a swimmer a firmer material with which to push off of. Gettelfinger and Cussler [37] recently established that these two effects effectively cancel each other out for human swimmers. Their experiment was so humorously dramatic, including competitive collegiate swimmers in a pool of guar, that it netted a 2005 IgNobel Prize for Chemistry. ...
We present an algorithm for creating realistic animations of characters that are swimming through fluids. Our approach combines dynamic simulation with data-driven kinematic motions (motion capture data) to produce realistic animation in a fluid. The interaction of the articulated body with the fluid is performed by incorporating joint constraints with rigid animation and by extending a solid/fluid coupling method to handle articulated chains. Our solver takes as input the current state of the simulation and calculates the angular and linear accelerations of the connected bodies needed to match a particular motion sequence for the articulated body. These accelerations are used to estimate the forces and torques that are then applied to each joint. Based on this approach, we demonstrate simulated swimming results for a variety of different strokes, including crawl, backstroke, breaststroke, and butterfly. The ability to have articulated bodies interact with fluids also allows us to generate simulations of simple water creatures that are driven by simple controllers.
Microbot propulsion requires unique strategies due to the dominance of viscosity and the reversible nature of microscale flows. To address this, swimmers of specific structure that translate in bulk fluid are commonly used; however, another approach is to take advantage of the inherent asymmetry of liquid/solid surfaces for microbots (μbots) to walk or roll. Using this technique, we have previously demonstrated that superparamagnetic colloidal particles can be assembled into small μbots, which can quickly roll along solid surfaces. In an analogous approach, here we show that symmetry can be similarly broken near air/liquid interfaces and μbots propelled at rates comparable to those demonstrated for liquid/solid interfaces.
The Ig Nobel Prizes have been given out every year since 1991 by the international science humor magazine Annals of Improbable Research or AIR as it is more commonly known. The 2005 ceremony was held on October 6th at Harvard University’s historic Sanders Theatre. It was attended by a live audience of 1,200 lab coat and sundry attired individuals who continuously flooded the stage with paper airplanes and other ephemera. This was a slight inconvenience as the ceremony’s traditional stage sweeper, Harvard physics professor Roy Glauber, was not in attendance. Two days before the Ig Nobel Ceremony, he received a telephone call from Stockholm, informing him that he had been awarded a Nobel Prize in physics. Eight of the ten Ig Nobel Prize winners traveled to Harvard—at their own expense—to accept their prizes, which were handed to them personally by Nobel Laureates Dudley Herschback (Chemistry ‘86), William Lipscomb (Chemistry ‘76), Sheldon Glashow (Physics ‘79), and Robert Wilson (Physics ‘78). Wilson, by the way, was the prize in the annual Win-a-Date-with-a- 3 Nobel-Laureate Contest. (A video is available at http://www.improb .com—of the ceremony, not the date.)
1. Abstract The speed change of an object moving through fluid of different viscosity and density under the same power at constant speed is shown to be given by V 1 V 2 = µ 2 µ 1 ! " # % & b(1) * + + ,-.. 1 3b(1 where V 1 = total speed in fluid 1 V 2 = total speed in fluid 2 b = drag law exponent where the drag law form is given by C D = aRe-1/b. Thus the velocity change only depends on mechanical fluid properties and the drag law exponent in a simple way. The velocity change or ratio is a simple function of the viscosity and density ratios powered by the drag law exponent and doesn't depend on any body scales for identical objects.
Whatever some people may think about the IgNobef Prize, it still is a great honor in any case. So don't let the occasional killjoy discourage you or lessen your desire to win it. Just get started working on a research project that first makes people laugh and then makes them think. There is much to Ig-research, and if you have a promising project in mind, then go for it. Chemie in unserer Zeit will be crossing its fingers for you and if you win the prize, we will be sure to extensively report on your project. And that's a promise!
The lecture is an important and indispensible tool for teaching undergraduate chemical engineering students. The electronics revolution will not dramatically change the basic structure of the lecture, but supplement and enhance what is being taught. The lecture has three characteristics, such as content, format, and evaluation. Its content depends on the discipline in which the lecture is offered. Developing this content requires a consensus among those working in the field.
Wie immer man den Ig®Nobelpreis geschmacklich auch bewerten mag, eine Ehre ist es auf jeden Fall. Lassen Sie sich von gelegentlichen Miesmachern nicht entmutigen und die Lust auf den Ig®Nobelpreis verderben. Es gilt etwas zu Erforschen, das zuerst zum Lachen und dann zum Überlegen anregt. Es gibt viel zu IgForschen, und wenn Sie ein entsprechendes Forschungsprojekt im Sinn haben, dann packen Sie es an. Chemie in unserer Zeit drückt Ihnen die Daumen, und über die Preisverleihung an Sie werden wir an dieser Stelle ausführlich berichten. Versprochen!
Whatever some people may think about the IgNobel Prize, it still is a great honor in any case. So don't let the occasional killjoy discourage you or lessen your desire to win it. Just get started working on a research project that first makes people laugh and then makes them think. There is much to Ig-research, and if you have a promising project in mind, then go for it. Chemie in unserer Zeit will be crossing its fingers for you and if you win the prize, we will be sure to extensively report on your project. And that's a promise!
A survey is given on fluid-dynamic effects caused by the structure and properties of biological surfaces. It is demonstrated that the results of investigations aiming at technological applications can also provide insights into biophysical phenomena. Techniques are described both for reducing wall shear stresses and for controlling boundary-layer separation. (a) Wall shear stress reduction was investigated experimentally for various riblet surfaces including a shark skin replica. The latter consists of 800 plastic model scales with compliant anchoring. Hairy surfaces are also considered, and surfaces in which the no-slip condition is modified. Self-cleaning surfaces such as that of lotus leaves represent an interesting option to avoid fluid-dynamic deterioration by the agglomeration of dirt. An example of technological implementation is discussed for riblets in long-range commercial aircraft. (b) Separation control is also an important issue in biology. After a few brief comments on vortex generators, the mechanism of separation control by bird feathers is described in detail. Self-activated movable flaps (= artificial bird feathers) represent a high-lift system enhancing the maximum lift of airfoils by about 20%. This is achieved without perceivable deleterious effects under cruise conditions. Finally, flight experiments on an aircraft with laminar wing and movable flaps are presented.
This book provides a clear and concise summary of the fluid dynamics of the locomotion of living organisms. The biological phenomena described in detail range from the swimming of bacteria and fish to the flying of insects and birds. The breadth of treatment requires the study of two basic fluid-dynamical regimes. In the first case, that of small organisms, the viscosity of the fluid is paramount in deciding the most effective swimming strategy. However, for larger insects, birds, and most fish, the viscosity of the air or water may be treated as if it were zero, and resulting mechanisms of propulsion are very different. Both these types are studied, with emphasis on the unsteady character of natural movements. Written for the advanced student, this volume assumes familiarity with basic fluid mechanics, although some elementary topics are included. It will be readily accessible to students of applied mathematics and biologists who have engineering or physics backgrounds.
A cross-sectional comparison between the buoyancy, passive and net active drag force characteristics of full-length, Fastskin swimsuits with that of standard swimsuits was completed with nine Open National level swimmers (5 males and 4 females). Subjects were weighed in a hydrostatic tank and then towed via a mechanical winch on the surface and 0.4 m deep at 1.6, 2.2 and 2.8 m/s. The subjects performed a prone streamlined glide and maximum effort flutter kick at each towing velocity and depth. Hydrostatic weight differences between swimsuit types were not significant (p> 0.05. Fastskin passive drag values were significantly less than normal swimsuits during surface towing at 1.6 and 2.8 m/s: and at 0.4 m deep towing at 1.6, 2.2 and 2.8 m/s. Net active drag force values also were lower for the Fastskin suits when compared with those of normal swimsuits and a significant difference existed for surface towing at all three velocities of 1.6, 2.2 and 2.8 m/s. The full-length, Fastskin swimsuits created less total hydrodynamic resistance than normal swimsuits while providing no additional buoyancy benefits.
The effect on drag of a Speedo Fast-skin suit compared to a conventional suit was studied in 13 subjects (6 males, 7 females) swimming at different velocities between 1.0 and 2.0 m.s-1. The active drag force was directly measured during front crawl swimming using a system of underwater push-off pads instrumented with a force transducer (MAD system). For a range of swimming speeds (1.1, 1.3, 1.5 and 1.7 m.s-1), drag values were estimated. On a group level, a statistically non-significant drag reduction effect of 2% was observed for the Fast-skin suit (p = 0.31). Therefore, the 7.5% reduction in drag claimed by the swimwear manufacturer was not corroborated.
- H M Toussaint
- A P De Hollander
- C Van Der Berg
- A R Vorontsov
Toussaint, H. M., A. P. de Hollander, C. van der Berg, and A. R.
Vorontsov, " Biomechanics of Swimming " Exercise and Sport Science,
W. E. Garrett and D. T. Kirkendall, eds., Lippencott, Wilhams, and
Wilkins, Philadelphia, p. 139 (2000)