scholarly journals Ring thruster — a preliminary optimisation study

2009 ◽  
Vol 16 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Leszek Matuszewski
Keyword(s):  
Computer Code ◽  
Hydrodynamic Characteristics ◽  
Significant Feature ◽  
Design Procedures ◽  
Cavitation Tunnel ◽  
New Type ◽  
Computer Codes ◽  
The Subject ◽  
Propeller Blades ◽  
Design Calculations

Ring thruster — a preliminary optimisation study The ring thruster is a new type of propeller, for which there is no experimental data to verify analytical design calculations. A significant feature of the ring thruster is the absence of a shaft. Propeller blades are mounted to the ring rotating inside the housing, which has the shape of a nozzle. For this reason the ring thruster is closest, with respect to both the construction and principle of operation, to the Kort nozzle propeller. The absence of a shaft and no gap between the blades and the nozzle make it impossible to fully relay on results obtained from Kort nozzle propeller examination. What is more, the already existing computer codes developed for designing Kort nozzle propellers cannot be directly used for designing ring thrusters either. That is why for this purpose a new code determining hydrodynamic characteristics based on the theory of the vortex lifting surface will be used. When using the above method, some differences between calculated and experimentally recorded results are expected to be observed. To a significant extent, the level of the torque taken by the thruster will be affected by drag of the rotating ring to which the blades are fixed. Examining a propeller equipped with a rotating ring has revealed that the expected torque increment may reach as much as a few per cent, at the comparable level of axial force (thrust). At the present stage of ring propeller investigations there is no data available on how to shape the ring propeller blades. Possible comparison calculations, done using the existing computer code, will allow, the most, the shape of the blades to be determined for preliminary tests in the cavitation tunnel and on a self-propelled model. And only the results obtained in these tests will provide opportunities for verification of preliminary design calculations. It should be stressed, however, that developing design procedures for this type of propellers will require additional optimisation calculations, with further experimental verification. And this should be the subject of separate investigations.

scholarly journals An experimental and numerical study of the vortices generated by hydrofoils

2009 ◽  
Vol 16 (3) ◽  
pp. 11-17 ◽  
Author(s):  
J. Szantyr ◽  
R. Biernacki ◽  
P. Flaszyński ◽  
P. Dymarski ◽  
M. Kraskowski
Keyword(s):  
Velocity Field ◽  
Cross Sections ◽  
Numerical Study ◽  
Turbulence Models ◽  
Marine Propeller ◽  
Flow Conditions ◽  
Tip Vortices ◽  
Cavitation Tunnel ◽  
Computer Codes ◽  
Propeller Blades

An experimental and numerical study of the vortices generated by hydrofoils The article presents the results of the research project concerning the process of formation of the tip vortices shed from hydrofoils of different geometry in different flow conditions. Three hydrofoils resembling the contemporary marine propeller blades have been selected for the study. The experimental part of the project consisted of the LDA measurements of the velocity field in three cross-sections of the vortex generated by the hydrofoils in the cavitation tunnel. The numerical part of the project consisted of calculations of the corresponding velocity field by means of three computer codes and several selected turbulence models. The comparative analysis of the experimental and numerical results, leading to the assessment of the accuracy of the numerical methods, is included.

Temperature and Smoke Prediction in Structural Fires

2001 ◽  
Author(s):  
Hyeong-Jin Kim ◽  
David G. Lilley
Keyword(s):  
Experimental Data ◽  
Fire Behavior ◽  
Computer Code ◽  
Fire Spread ◽  
Temperature Measurements ◽  
Fire Scenarios ◽  
Computer Codes ◽  
Actual Fire ◽  
The Subject ◽  
Structural Fires

Abstract Temperature and smoke level predictions in several rooms of a structural fire are possible with a variety of available computer codes. The accuracy and applicability of the results is greatly enhanced though the comparison of the calculations with experimental data. Experimental work assists in understanding fire behavior in structural fires. Temperature measurements at different locations during a house fire provide necessary data for the development of mathematical models, which attempt to simulate the fire on a computer. In this paper, a small 46 square meter single-level house was the subject of a complete experimental burn, with temperature measurements and fire observations during the entire burn. The CFAST computer code (Consolidated Model of Fire Growth and Smoke Transport) can be used to calculate temperatures and smoke levels in the various rooms of the house during the burn. Five fire scenarios are considered in the simulation, with progressively increasing realism regarding the actual fire specification. It is seen that calculations with the most realistic fire simulation (permitting burning in all rooms during the course of the fire) are in very good agreement with the experimental data, with regard to rate of fire spread throughout the structure, and the accuracy of the calculations of flashover, temperatures and smoke levels in each of the rooms.

Dynamic Positioning Thruster Near Wake Hydrodynamic Characteristics at Near Bollard Pull

2009 ◽  
Vol 53 (01) ◽  
pp. 48-58
Author(s):  
Said A. El Lababidy ◽  
Neil Bose ◽  
Pengfei Liu ◽  
Dan Walker
Keyword(s):  
System Reliability ◽  
Laser Doppler Velocimetry ◽  
Diameter Ratio ◽  
Operating Conditions ◽  
Hydrodynamic Characteristics ◽  
Dynamic Positioning ◽  
Doppler Velocimetry ◽  
Near Wake ◽  
Two Component ◽  
Cavitation Tunnel

The knowledge of the hydrodynamic characteristics and momentum effects of the flow of dynamic positioning (DP) thrusters are important factors in the design of structures around the DP thrusters and in improving DP system reliability. In the present study, the flow field around a DP thruster model was precisely measured in a cavitation tunnel using a two-component laser Doppler velocimetry (LDV) system. These experiments were carried out with and without a nozzle at three different axial planes up to 1.5 diameters downstream, and the results are presented here for a pitch/diameter ratio of 1.2 at near bollard pull operating conditions (J ¼ 0.4 and J ¼ 0.45). This paper shows and compares the results of the DP thruster near wake hydrodynamic and momentum characteristics when operating with and without a nozzle at two different low advance coefficient values.

The Organization of Life before Death in Two Québec Cultural Configurations

1993 ◽  
Vol 27 (1) ◽  
pp. 35-50
Author(s):  
Luce Des Aulniers
Keyword(s):  
Basic Concept ◽  
Data Gathering ◽  
Doctoral Thesis ◽  
Historical Factors ◽  
Personal Experiences ◽  
Life Threatening ◽  
New Type ◽  
The Subject ◽  
Fatal Illness ◽  
Data Gathering And Analysis

This article is based on data from a doctoral thesis about the “anthropology of life-threatening, death and time.” [1] The interpretation is made from twelve life reviews set at homes of people who suffered a serious, but not necessarily fatal illness. Two-cultural configurations are chosen along the axis of rural-urban polarity. It focuses on three types of solidarity, facing the awareness of death: 1) the ethnographic position, in data gathering and analysis. Specific propositions are given concerning the subject and intersubjectivity, cultural generalization of personal experiences, and scientific criteria; 2) what helps cope with illness. Pre-death practices are structured on the basic concept of resistance to illness and preparation for death practices rely on a coherence “test.” The genealogy of practices emerge in six situational and seven historical factors; 3) the conditions of a new type of rite before death and its functions, beside the institutionalization of illness and death.

scholarly journals EXPERIMENTAL ONLINE CASE STUDY FOR A BREAKTHROUGH IN STUDENT ENGAGEMENT: FOCUS GROUP RESULTS

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
James Theroux ◽  
Cari Carpenter ◽  
Clare Kilbane
Keyword(s):  
Student Engagement ◽  
Focus Group ◽  
Real Time ◽  
Group Discussion ◽  
Full Time ◽  
The Real ◽  
Building Process ◽  
New Type ◽  
The Subject

A new type of case study, called the real-time case (RTC), was produced in the fall of 2001 and distributed via the Internet to business classes at four universities in the US and Canada. The real-time case presented the story of one company's growth and development throughout a 14-week semester. A case writer stationed full-time at the subject company published case installments weekly on the Web, allowing students to view the company-building process as it happened. The 14-week coverage of RTC enabled students to study the subject company in unprecedented depth and detail. RTC's real-time interactivity allowed students to share their analyses and best thinking with the company leadership during the company’s decision-making process.A major objective in producing the case was to heighten student engagement with the case material. To evaluate whether this objective was achieved, a survey and a focus group discussion were conducted with one of the participating MBA classes. Results from the survey and the focus group showed a high degree of engagement, plus many other benefits from the new type of case study.

scholarly journals Scientia est potentia

2009 ◽  
pp. 43-60
Author(s):  
Ülo Kaevats
Keyword(s):  
Modern Science ◽  
New Approach ◽  
Natural Laws ◽  
Modern Times ◽  
Natural Objects ◽  
Deductive Method ◽  
New Type ◽  
The Subject ◽  
Understanding Of Science ◽  
Object Of Study

Oma algses mitmetähenduslikkuses on see F. Baconi aforism kõige tihendatum tõdemus, mis tõmbab olemusliku eraldusjoone ühelt poolt antiikse ja keskaegse ning teisalt uusaegse arusaama vahele teadusest ja teadusteadmisest. Artiklis püüab autor anda võimaluste piires tervikpildi uusaja teaduse industriaalselt (tehnoloogiliselt) orienteeritud teadmistüübi tekkimisest. Uusaja teaduse kujunemiseks vajaliku pöörde maailmavaateliste eeldustena tuleb käsitleda: (1) põhimõtteliselt uut subjekti ja objekti käsitust; (2) täiesti uut väärtusruumi, uut teaduse ideoloogiat (ilmalikkus, kriitiline vaim, tõesus ja praktiline kasulikkus); (3) tunnetuslaadi muutust — kontemplatsioonilt interventsioonile, kvaliteedi kirjeldamiselt kvantiteedi uurimisele; (4) looduse käsitlemist Kosmose asemel seaduspäraselt korrastatud objektide “väljana”. Uue tunnetusstiili — empiirilise ja teoreetilise tunnetuse kokkuviimine, hüpoteetilis-deduktiivse metodoloogia kujundamine Galilei poolt, abstraktse ja sünteetilis-tekstilise loomuga spekulatsiooni asendumine uurimisobjekti ehituse, korrapära ja põhjuslikkuse objektiivse analüüsiga, universaalsete loodusseaduste doktriini kujunemine jms—kujunemine konstitueeris uut tüüpi teadmise. Teadmise kui nähtava maailma piltkoopia asemele luuakse teadmine kui loodusobjektide seaduspära analüütiline rekonstruktsioon. See on vormiltmatemaatiline, päritolult eksperimentaalne ning loodusobjektide kontrollimisele ja ümbertegemisele suunatud nn valdamisteadmine.This F. Bacon's aphorism in its original ambiguity is the most condensed belief that draws a distinctive essential line between ancient and medieval understanding of science and scientific knowledge on one hand and modern understanding on the other. The author aims at providing, as far as possible, an integral overview of emerging of the industrially (technologically) orientated type of knowledge of modern times. Ideological/philosophical preconditions of the change necessary for emerging of modern science are: (1) a fundamentally new approach to the subject and object; (2) a completely new system of values, a new ideology of science (secularity, critical spirit, trueness and utilitarianism); (3) a change in manner of cognizance - from contemplation to intervention, from describing quality to studying quantity; (4) treating nature as a naturally organised "field" of objects instead of the Cosmos. Emerging of a new style of cognizance - bringing together of empirical and theoretical cognition, the devise of the hypothetical-deductive method by Galilei, replacement of speculations abstract and synthetic-textual in nature with objective study of the structure, regularity and causality of the object of study, establishment of the doctrine of universal natural laws etc - constituted a new type of knowledge. Knowledge as a copy of the visible world is replaced by knowledge as an analytical reconstruction of the regularity of natural objects. It is so-called dispositive knowledge, morphologically mathematical, originally experimental and aimed at control and alteration of natural objects.

scholarly journals Ideological Phantoms of Civilisation and Culture: Identity and Tolerance

2019 ◽  
pp. 1-13
Author(s):  
Natalia Yu. Beregovaya ◽  
Olga A. Karlova
Keyword(s):  
Community Based ◽  
Culture Studies ◽  
Historical Method ◽  
Philosophical Aspect ◽  
New Type ◽  
The Subject ◽  
The Difference ◽  
Ideological Manipulation ◽  
Global World ◽  
Modelling Methods

The article considers the philosophical aspect of defining the immanence and attribution of the concept of “tolerance” to the culture itself. The subject of the research is especially relevant due to the modern processes that are happening in the global world, and the difference in key methodological positions of modern Russian and Western science on this issue today. The purpose of this study is to clarify the philosophical basis of the existing opposition of societies with traditional ethical cultures (Russia, China) and the ‘new-type’ poly-state European ethnic community. Based on the analysis of current social processes in Russia and Europe using the comparative historical method, modelling methods and model extrapolation in the field of culture studies, social psychology and political science, the article identifies the main approaches to ethnic and social identity, their cultural and ideological components. The authors prove the hypothesis that culture requires designation of its border with another culture, recognition of this border, which distinguishes and confirms cultural semantics. Denial of this fact is a method of ideological manipulation of the ethno-social consciousness of society in the framework of globalisation processes

scholarly journals Intimacy and its violation: on the experience of illness in contemporary women's poetry

2021 ◽  
Author(s):  
Beata Morzyńska-Wrzosek
Keyword(s):  
Hospital Setting ◽  
The Body ◽  
Women's Poetry ◽  
Research Perspective ◽  
Artistic Representations ◽  
Body Boundary ◽  
New Type ◽  
The Subject ◽  
Experience Of Illness ◽  
Subjective Identity

This article discusses selected aspects of the problem of self-perception by a sick individual, specific to the poetry of Polish women of the last few decades. The aim of the analysis is to show that the body is central to the illness experience and that a new type of intimacy appears in connection with its ailment. This is a „clinical intimacy”, the specificity of which is defined by a confrontation with suffering, the proliferation of the feeling of isolation, the intensity of emotions related to making the body public, its discovery and exposure in a hospital setting. The issue of „gender expropriation” in a marginal situation is also important, as is the scar, wound, physical violation of the body boundary, read as the „punctum” of the patient's body. The interpretation emphasises the individualization of artistic representations of the aforementioned aspects of „clinical intimacy”. The anthropological research perspective adopted in the sketch allows for the diagnosis of the subject matter in the context of the process of shaping subjective identity.

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