Viscous Flow Computation around the Wigley Hull with the Maneuvering Motion using the Inertial Coordinate System on the Non-inertial Grids

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Yan Naing Win ◽  
Yasuyuki Toda
Keyword(s):  
Flow Field ◽  
Degrees Of Freedom ◽  
The Body ◽  
Uniform Motion ◽  
Ocean Engineering ◽  
Blade Element Theory ◽  
Wigley Hull ◽  
Computational Fluid Dynamics Cfd ◽  
The One ◽  
Element Theory

Computational Fluid Dynamics (CFD) technique for ship hydrodynamics has been well developed with advanced capabilities for resistance and propulsion, seakeeping, and maneuvering. The Authors’ laboratory (Laboratory 3 of Department of Naval Architecture and Ocean Engineering in Osaka University) specializes in resistance and propulsion field and has carried out several simulations based on the CFD code in non-inertial ship-fixed coordinates system. The purpose of this research is to transform the present computation code to the one in inertial coordinate and to investigate the flow field around the Wigley hull for several motions up to three degrees of freedom (3 DOF). The transformed code is simulated on the flat plate initially and the nature of the flow field is investigated and confirmed with the hydrodynamics theory. Then, the wigley hull motions are simulated in several ways such as; uniform motion, pure yaw and circular motion test. The features of the flow field and hydrodynamic forces acting on the hull are discussed based on the computed results. Finally, the propeller effect is implemented behind the wigley hull using the body-force concept by the quasi-steady infinite bladed Blade Element Theory and a propulsion characteristic is observed. The transformed computation code in inertial coordinate is found to be much easier to simulate the different kinds of maneuvering motions compared to the code in non-inertial system and this paper covers the detailed transformation steps and the discussions on the computation results of different motions.

Generalized Kirchhoff equations for a deformable body moving in a weakly non-uniform flow field

1994 ◽  
Vol 446 (1926) ◽  
pp. 169-193 ◽  
Keyword(s):  
Flow Field ◽  
Rigid Body ◽  
Degrees Of Freedom ◽  
Surface Deformation ◽  
Nonlinear Differential Equations ◽  
Deformable Body ◽  
Equations Of Motion ◽  
First Integral ◽  
Uniform Flow ◽  
The Body

The classical Kirchhoff’s method provides an efficient way of calculating the hydrodynamical loads (forces and moments) acting on a rigid body moving with six-degrees of freedom in an otherwise quiescent ideal fluid in terms of the body’s added-mass tensor. In this paper we provide a versatile extension of such a formulation to account for both the presence of an imposed ambient non-uniform flow field and the effect of surface deformation of a non-rigid body. The flow inhomogeneity is assumed to be weak when compared against the size of the body. The corresponding expressions for the force and moment are given in a moving body-fixed coordinate system and are obtained using the Lagally theorem. The newly derived system of nonlinear differential equations of motion is shown to possess a first integral. This can be interpreted as an energy-type conservation law and is a consequence of an anti-symmetry property of the coefficient matrix reported here for the first time. A few applications of the proposed formulation are presented including comparison with some existing limiting cases.

CFD-BASED SELF-PROPULSION SIMULATION FOR FROG SWIMMING

2014 ◽  
Vol 14 (06) ◽  
pp. 1440012 ◽  
Author(s):  
JIZHUANG FAN ◽  
WEI ZHANG ◽  
YANHE ZHU ◽  
JIE ZHAO
Keyword(s):  
Flow Field ◽  
Large Range ◽  
Hydrodynamic Forces ◽  
The Body ◽  
Joint Motion ◽  
Mechanism Analysis ◽  
Hydrodynamic Problem ◽  
Pressure Distributions ◽  
Body Velocity ◽  
Computational Fluid Dynamics Cfd

Mechanism analysis of frog swimming is an interesting subject in the field of biofluid mechanics and bionics. Computing the hydrodynamic forces acting on a frog is difficult due to its characteristics of explosive propulsion and large range of joint motion. To analyze the flow around the body and vortices in the wake, in this paper, the method based on Computational Fluid Dynamics (CFD) was utilized to solve the velocity and pressure distributions in the flow field and on the frog. The hydrodynamic problem during the propulsive phase of a frog, Xenopus laevis, was calculated using the CFD software FLUENT. A self-propulsion simulation was performed which computed the body velocity from the joint trajectory input and CFD solved the hydrodynamic forces, and visual CFD results of the hydrodynamic forces and flow field structures were obtained.

Bayesian Optimization Based Terrestrial Gait Tuning for a 12-DOF Alligator-Inspired Robot With Active Body Undulation

2018 ◽  
Author(s):  
Krishna Agrawal ◽  
Kushagra Jain ◽  
Dhawal Gupta ◽  
Raunak Srivastav ◽  
Abhijeet Agnihotri ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Critical Role ◽  
Parameter Tuning ◽  
The Body ◽  
Experimental Results ◽  
Bayesian Optimization ◽  
Terrestrial Locomotion ◽  
Gait Parameters ◽  
Rotational Degrees Of Freedom ◽  
The One

In addition to aiding in swimming, body undulation of an alligator plays a critical role in terrestrial locomotion by imparting stability. This paper reports design, fabrication and terrestrial locomotion control incorporating active body undulation of a 12-DOF alligator-inspired robot. Each of the four legs of the developed robot has two rotational degrees of freedom while the body can perform undulation using additional four rotational degrees of freedom. This paper also presents a Bayesian optimization based approach to tune the gait parameters of both leg oscillation and body undulation in order to maximize the average robot speed. We obtained improvement by a factor of 1.93 in average robot speed in comparison to the one obtained by randomly generated parameters and report the experimental results in this paper. In future, we plan to generalize the developed Bayesian optimization based parameter tuning approach for the swimming gait and thereby impart amphibious capabilities to the developed robot.

Design of Upswept Aft-Body of Civil Transport Based on CFD

2013 ◽  
Vol 690-693 ◽  
pp. 2722-2725
Author(s):  
Mu Qing Yang ◽  
Dong Li Ma ◽  
Ya Feng Liu ◽  
Wen Yue Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Friction Drag ◽  
Total Drag ◽  
Pressure Drag ◽  
Computational Fluid Dynamics Cfd ◽  
The One

Study on flow field of civil transport upswept aft-body is of much value as the drag coursed by aft-body contributes to about 10 percent of total drag. Currently researches were mostly concerned on clean fuselage, while little emphasis was put on fuse-tail configuration. With interests to exploiting the effect of design parameters on fuselage with empennage, computational fluid dynamics (CFD) was used to simulate the flow field of fuselages with different parameters. Based on studying the aerodynamic performance of clean fuselages, emphases were placed on fuse-tail configurations. Although fairing at root of stabilizer is good for reducing pressure drag, influence on friction drag should be taken into consideration when determine the design of fairing. With stabilizer mounted, drag of axial symmetric fuselage is not the minimum, while the one with some angle upswept is drag optimal.

Representing utility and deploying the body

2020 ◽  
Vol 43 ◽  
Author(s):  
David Spurrett
Keyword(s):  
Functional Activity ◽  
Degrees Of Freedom ◽  
The Body ◽  
Target Article ◽  
Processing Demands ◽  
The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

‘If you shoulder a rifle […] let it be for Ireland’: James Connolly's War on War

2018 ◽  
Vol 13 (3) ◽  
pp. 364-381
Author(s):  
Margot Gayle Backus ◽  
Spurgeon Thompson
Keyword(s):  
World War I ◽  
The Body ◽  
Party Leader ◽  
Irish Nationalism ◽  
British Imperialism ◽  
Communications Networks ◽  
Easter Rising ◽  
Trade Unionist ◽  
The One ◽  
National Governments

As virtually all Europe's major socialist parties re-aligned with their own national governments with the outbreak of World War I, Irish socialist and trade unionist James Connolly found himself internationally isolated by his vociferous opposition to the war. Within Ireland, however, Connolly's energetic and relentless calls to interrupt the imperial transportation and communications networks on which the ‘carnival of murder’ in Europe relied had the converse effect, drawing him into alignment with certain strains of Irish nationalism. Connolly and other socialist republican stalwarts like Helena Molony and Michael Mallin made common cause with advanced Irish nationalism, the one other constituency unamenable to fighting for England under any circumstances. This centripetal gathering together of two minority constituencies – both intrinsically opposed, if not to the war itself, certainly to Irish Party leader John Redmond's offering up of the Irish Volunteers as British cannon fodder – accounts for the “remarkably diverse” social and ideological character of the small executive body responsible for the planning of the Easter Rising: the Irish Republican Brotherhood's military council. In effect, the ideological composition of the body that planned the Easter Rising was shaped by the war's systematic diversion of all individuals and ideologies that could be co-opted by British imperialism through any possible argument or material inducement. Although the majority of those who participated in the Rising did not share Connolly's anti-war, pro-socialist agenda, the Easter 1916 Uprising can nonetheless be understood as, among other things, a near letter-perfect instantiation of Connolly's most steadfast principle: that it was the responsibility of every European socialist to throw onto the gears of the imperialist war machine every wrench on which they could lay their hands.

The Woman Who Turned Into a Jaguar, and Other Narratives of Native Women in Archives of Colonial Mexico

2017 ◽  
Author(s):  
Lisa Sousa
Keyword(s):  
Gender Relations ◽  
Civil Disobedience ◽  
Indigenous Communities ◽  
The Body ◽  
Colonial Rule ◽  
Criminal Records ◽  
Native Women ◽  
Women's Lives ◽  
Important Position ◽  
The One

The Woman Who Turned Into a Jaguar examines gender relations in indigenous societies of central Mexico and Oaxaca from the 1520s to the 1750s, focusing mainly on the Nahua, Ñudzahui (Mixtec), Bènizàa (Zapotec), and Ayuk (Mixe) people. This study draws on an unusually rich and diverse corpus of original sources, including Ñudzahui- (Mixtec-), Tíchazàa- (Zapotec-), and mainly Nahuatl-language and Spanish civil and criminal records, published texts, and pictorial manuscripts. The sources come from more than 100 indigenous communities of highland Mexico. The book considers women’s lives in the broadest context possible by addressing a number of interrelated topics, including: the construction of gender; concepts of the body; women’s labor; marriage rituals and marital relations; sexual attitudes; family structure; the relationship between household and community; and women’s participation in riots and other acts of civil disobedience. The study highlights subtle transformations and overwhelming continuities in indigenous social attitudes and relationships. The book argues that profound changes following the Spanish conquest, such as catastrophic depopulation, economic pressures, and the imposition of Christian marriage, slowly eroded indigenous women’s status. Nevertheless, gender relations remained inherently complementary. The study shows how native women and men under colonial rule, on the one hand, pragmatically accepted, adopted, and adapted certain Spanish institutions, concepts, and practices, and, on the other, forcefully rejected other aspects of colonial impositions. Women asserted their influence and, in doing so, they managed to retain an important position within their households and communities across the first two centuries of colonial rule.

scholarly journals Experiential ownership and body ownership are different phenomena

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caleb Liang ◽  
Wen-Hsiang Lin ◽  
Tai-Yuan Chang ◽  
Chi-Hong Chen ◽  
Chen-Wei Wu ◽  
...  
Keyword(s):  
Conscious Experience ◽  
Distinct Type ◽  
Body Part ◽  
The Body ◽  
Body Ownership ◽  
Rubber Hand ◽  
Person Perspective ◽  
The One ◽  
First Time ◽  
Full Body

AbstractBody ownership concerns what it is like to feel a body part or a full body as mine, and has become a prominent area of study. We propose that there is a closely related type of bodily self-consciousness largely neglected by researchers—experiential ownership. It refers to the sense that I am the one who is having a conscious experience. Are body ownership and experiential ownership actually the same phenomenon or are they genuinely different? In our experiments, the participant watched a rubber hand or someone else’s body from the first-person perspective and was touched either synchronously or asynchronously. The main findings: (1) The sense of body ownership was hindered in the asynchronous conditions of both the body-part and the full-body experiments. However, a strong sense of experiential ownership was observed in those conditions. (2) We found the opposite when the participants’ responses were measured after tactile stimulations had ceased for 5 s. In the synchronous conditions of another set of body-part and full-body experiments, only experiential ownership was blocked but not body ownership. These results demonstrate for the first time the double dissociation between body ownership and experiential ownership. Experiential ownership is indeed a distinct type of bodily self-consciousness.

scholarly journals Knowledge, authority, and positionality in Asian immigrant female faculty teaching diversity classes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jung-ah Choi ◽  
Jae Hoon Lim
Keyword(s):  
Multicultural Education ◽  
Professional Knowledge ◽  
Teaching Experience ◽  
Faculty Of Color ◽  
The Body ◽  
Power Dynamics ◽  
Safe Environment ◽  
Faculty Teaching ◽  
The One ◽  
Body Knowledge

AbstractThis paper is a self-reflective narrative of our teaching experience as two immigrant Asian female professors who teach Multicultural Education. Employing collaborative autoethnography (CAE), the study addresses the issues of authority, positionality, and legitimacy of knowledge claims in critical feminist pedagogy. Two research questions guided our inquiry: 1. How does a teacher’s racial positionality play out in exercising professional knowledge, and conversely, 2. How does seemingly neutral professional knowledge become racialized in the discussions of race? Major findings demonstrate the double-edged contradictions in the body/knowledge nexus manifested in our everyday teaching contexts. On the one hand, the bodily dimension of teacher knowledge is de-racialized because of institutional norms and cultures. On the other hand, there are times professional knowledge becomes racialized through the teacher’s body. Understanding the body/knowledge nexus that invites precarious power dynamics in racial discussions and even blatantly dismisses our professional knowledge, we, as an immigrant faculty of color, find it impossible to create a safe environment for participatory, critical discourse. Acknowledging our triple marginality, we put forth the concept of “pedagogy of fear” (Leonardo, Z., & Porter, R. K. (2010). Pedagogy of fear: Toward a Fanonian theory of ‘safety’ in race dialogue. Race, Ethnicity and Education, 13(2), 139–157) which squarely disrupts the idea of a safe environment in race dialog and urges teachers to confront their own/their students’ fear and create a space of teaching vulnerably.

SEEING AND HEARING DISABILITY IN MAURICIO KAGEL'S REPERTOIRE FROM STAATSTHEATER

Tempo ◽  
2021 ◽  
Vol 75 (296) ◽  
pp. 7-20
Author(s):  
Bethany Younge
Keyword(s):  
Disability Studies ◽  
Social Institutions ◽  
The Body ◽  
Avant Garde ◽  
Hearing Disability ◽  
Physical Action ◽  
The One ◽  
Traditional Roles

AbstractThis article adopts a disability studies perspective to evaluate the ways in which Mauricio Kagel's Repertoire from Staatstheater reimagines human bodies. Objects and bodies interact in myriad ways within the one hundred vignettes of Repertoire: some objects hinder or aid the bodies on stage, while others become incorporated within the body, acting as a single expressive unit. My analysis demonstrates the ways in which both objects and bodies transform their traditional roles as ascribed by society, rejecting procrustean physiques. Using disability studies concepts such as embodiment and experientialism I evaluate sound and physical action as inextricable expressions of imaginative corporealities. Reflecting upon Kagel's identity as an outsider of the European avant-garde, as well as his irreverence for oppressive social institutions, I evince that other forms of hierarchical disruptions are at play, namely that abled bodies do not preside over disabled ones and notions of beauty hold no clout.

Sign in / Sign up

Export Citation Format

Share Document