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Safety Profile of Trocar and Insufflation Needle Access Systems in Laparoscopic Surgery

PASSEROTTI, Carlo C.; BEGG, Nikolai; PENNA, Frank J.; PASSEROTTI, Ana Maria A. M. S.; LEITE, Katia R. M.; ANTUNES, Alberto Azoubel; Srougi, Miguel; RETIK, Alan B.; NGUYEN, Hiep T.
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.19%
BACKGROUND: The most common laparoscopic complications are associated with trocar insertion. The purpose of this study was to develop an objective method of evaluating the safety profile of various access devices used in laparoscopic surgery. STUDY DESIGN: In 20 swine, 6 bladed and 2 needle access devices were evaluated. A force profile was determined by measuring the force required to drive the trocar or needle through the fascia and into the peritoneum, at 0 and 10 mmHg. The amount Of tissue deformation, the length of blade exposed, and the duration of exposure were measured using a high-speed digital imaging system. RESULTS: The needle system without the sheath required the least driving force and had the most favorable force profile. In contrast, the bladed, nonretractable trocar system required a higher driving force and a rapid loss of resistance. Insertion under a pneumoperitoneum did not significantly alter the force profile of the various access devices except for the amount of tissue deformation. With the bladed system, the blade itself was exposed for an average of 0.5 to 1.0 seconds for a distance of 4.5 to 5.0 cm. In comparison, the needle system was exposed for 0.2 seconds for a distance of 1.8 cm. CONCLUSIONS: We developed a reproducible method of measuring the forces required to place the access systems...

Escalonamento de tanques condicionadores utilizados na flotação de apatita.; Scale-up of stirred tanks for reagent conditioning at apatite flotation.

Sousa, Paulo Rogério Meneses de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/12/2010 PT
Relevância na Pesquisa
15.95%
Este trabalho estudou a aplicação de oito métodos clássicos de escalonamento de tanques condicionadores, testando sua validade para dois tanques de geometria semelhante, mas com diferentes volumes (V1=10 e V2=49 decímetros cúbicos). No interior dos tanques, operavam impulsores (diâmetro D1=0,078m x D2=0,132m) que exibiam três distintos desenhos (2 pás versus 4 pás inclinadas em 45 graus versus turbina de Rushton). Sua rotação (N1 no tanque menor x N2 no tanque maior) visava à suspensão de partículas grossas de apatita (diâmetro médio = 254 micrometros) em polpas com 40% de sólidos em massa. Para balizar o escalonamento, adotou-se como variável de controle a mínima rotação do impulsor (Njs) que é capaz de fazer com que nenhuma partícula repouse no fundo do tanque por mais do que 1 ou 2 segundos (Critério 1-s), além de perfis axiais de distribuição de sólidos e a extensão da Zona Turbulenta versus Zona Quiescente no interior dos tanques. A diferença entre o valor previsto de Njs para o tanque de 49 decímetros cúbicos (N2) pelos métodos de escalonamento versus o valor de Njs (N2) determinado experimentalmente foi expressa como erro percentual (E). Consideraram-se como adequados para a aplicação que constitui o objetivo desta dissertação todos os métodos que exibiram E menor que 10%. Para o impelidor de 2 pás inclinadas...

Estudo de rotor para turbina eólica de eixo horizontal de pequeno porte com aplicação de modelagem e simulação virtual; Study for small horizontal axis wind turbine rotor with application of modeling and virtual simulation

Pires, Julio César Pinheiro
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
26.13%
Este trabalho apresenta um estudo para aerogerador de pequeno porte projetado inicialmente para uso residencial. A ênfase está na modelagem e simulação virtual da estrutura das pás em compósito de fibra de vidro. A modelagem geométrica foi feita com software para desenho assistido por computador (CAD 3D). Para o projeto, foi escolhido o perfil MH110 que apresenta boa relação entre coeficiente de sustentação e coeficiente de arrasto e facilidade de fabricação. Os parâmetros como o diâmetro do rotor, a corda e a torção da pá, as relações entre velocidades e a aplicação de cargas na estrutura do material utilizado foram definidos segundo bibliografia específica, software para análise de perfil aerodinâmico e simulações pelo método dos elementos finitos. Procurou-se buscar sempre a maior eficiência, segurança e economia. O material considerado para o projeto das pás foi projetado para resistir às tensões decorrentes de operação em condições consideradas normais e para rajadas de vento. A simulação pelo método dos elementos finitos foi conduzida com ferramenta computacional e levou em conta os limites de falha do material utilizado. A geometria foi simulada sem reforço interno e apresentou baixo deslocamento quando submetida às cargas aerodinâmicas de empuxo e rotacional. Ao realizar simulação com critério de falha...

Modelagem e simulação virtual de pá para aerogerador de pequeno porte; Modelagem e simulação virtual da pá para rotor eólico de pequeno porte; Modeling and virtual simulation of blade for small wind rotor

Pires, Julio César Pinheiro; Oliveira, Branca Freitas de
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
36.18%
Este trabalho apresenta um estudo para aerogerador de pequeno porte projetado para uso residencial. A ênfase está na modelagem e simulação virtual da estrutura das pás em composito de fibra de vidro. A modelagem foi feita com software para desenho assistido por computador (CAD 3D). Para o projeto, foi escolhido o perfil MH110 que apresenta boa relação entre coeficiente de sustentação e coeficiente de arrasto e facilidade de fabricação. Os parâmetros como o diâmetro do rotor, a corda e a torção da pá, as relações entre velocidades e a aplicação de cargas na estrutura do material utilizado foram definidos segundo bibliografia específica, software para análise de perfil aerodinâmico e simulaçõees pelo método dos elementos finitos. Procurou-se buscar sempre a maior eficiência, segurança e economia. O material foi projetado para resistir as tensões decorrentes de operação em condiçõees consideradas normais e para rajadas de vento. A simulação pelo método dos elementos finitos foi conduzida com ferramenta computacional e levou em conta os limites de falha do material utilizado. A geometria foi simulada sem reforço interno e apresentou baixo deslocamento quando submetida às cargas aerodinâmicas de empuxo e rotacional. Ao realizar simulação com critério de falha...

Desempenho, características de carcaça e qualidade de carne de cordeiros Corriedale e Texel terminados em gramíneas tropicais; Performance, carcass characteristics and meat quality of lambs corriedale and texel finished in tropical grasses

Carnesella, Samuel
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
15.98%
Objetivou-se avaliar o potencial de gramíneas tropicais com distintos hábitos de crescimento para terminação de cordeiros para abate no outono. Para tal foram testadas três gramíneas tropicais: 1- Brachiaria brizantha cv. Marandu, 2 - Cynodon spp. cv Tifton-85 e 3 - Capim Aruana (Panicum maximum cv. IZ-5). Foi utilizado um delineamento experimental de blocos inteiramente ao acaso com parcelas subdivididas com três repetições. A parcela principal foi composta pelas três diferentes gramíneas tropicais. A subparcela foi composta por duas raças (Corriedale e Texel) com aptidões produtivas distintas. Durante 84 dias, 45 cordeiros foram mantidos em pastejo contínuo em piquetes com área de 0,2 hectares, com oferta de forragem disponível de 10% de lâmina foliar. Foram realizadas avaliações “in vivo”, ganho médio diário em peso (GMD), taxa de aumento da área de olho de lombo (TXAOL) e taxa de acúmulo de gordura subcutânea (TXEGS) em intervalos regulares de 21 dias. Ao final do período experimental, um total de 29 animais foi encaminhado para abate para avaliação de características quali-quantitativas de carcaça e qualidade da carne. O tratamento com B. brizantha cv. Marandu foi suspenso devido a casos de fotossensibilização. Não houve diferença para as variáveis GMD e TXEGS entre os tratamentos e entre raças ao final do período experimental (p>0...

Desenvolvimento de uma bancada de determinação da impedância acústica na presença de escoamento tangencial

Serrano, Pablo Giordani
Fonte: Universidade Federal de Santa Catarina Publicador: Universidade Federal de Santa Catarina
Tipo: Dissertação de Mestrado Formato: 199 p.| il., grafs., tabs.
POR
Relevância na Pesquisa
16.13%
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2014; A poluição sonora decorrente de tráfego aéreo é um dos principais problemas de comunidades que vivem nos arredores de aeroportos. Em aeronaves do tipo turbofan, um dos ruídos que mais se destacam nas condições de decolagem e pouso é o ruído tonal decorrente da passagem de pás da ventoinha do motor e conhecido como Blade Passage Frequency (BPF). Tal ruído é particularmente incômodo, e por esse fato, no cálculo do Effective Perceived Noise Level (EPNL) é inserida uma penalidade que pode ser determinante para a aceitação de uso da aeronave em um determinado aeroporto. O revestimento utilizado na parte interna do duto anular que contém o motor, conhecido como liner, atua passivamente ao atenuar o ruído da passagem de pás e contribui ao reduzir a penalidade no cálculo do EPNL. O parâmetro chave que caracteriza o liner é sua impedância acústica, que por sua vez é altamente sensível à presença de escoamento. Portanto, a determinação deste parâmetro em tais condições necessita de uma infra estrutura adequada que permita controlar e medir a velocidade de escoamento. Diversas bancadas de teste foram construídas com este propósito...

Concepção de uma pequena turbina eólica destinada ao segmento doméstico (simplificação e análise aerodinâmica das pás)

Alves, Edson Augusto de Brito
Fonte: Instituto Politécnico de Lisboa Publicador: Instituto Politécnico de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /11/2011 POR
Relevância na Pesquisa
16.32%
O trabalho que se apresenta incide sobre o estudo aerodinâmico das pás de uma turbina eólica de pequeno porte, com vista à simplificação geométrica, de forma a que estas sejam baratas e de fácil concepção. A teoria da quantidade de movimento do elemento de pá (BEMT), que é o modelo de referência para o projecto e análise aerodinâmica das pás das turbinas eólicas, foi utilizada neste trabalho de forma a projectar e analisar aerodinamicamente as pás da turbina. Sendo assim, desenvolveu-se um programa computacional em MATLAB, denominado de “Turbina”, de forma a implementar a teoria BEM. Introduzindo os dados dos parâmetros de projecto no programa (potência requerida, o número de pás, velocidade do vento, a TSR e o tipo de perfil alar), obtêm-se os parâmetros geométricos das pás (distribuição da corda ao longo da envergadura, o raio da pá e a distribuição da torção da pá), os parâmetros aerodinâmicos e de desempenho. Uma pá ideal foi calculada e de seguida foi modificada de forma a obter-se uma pá simples e menos carregada aerodinamicamente. Introduzidas as modificações na geometria da pá ideal, obtiveram-se duas configurações distintas. Uma configuração linear, onde a distribuição da corda e do ângulo de torção se tornam lineares...

Design and Development of Turbodrill Blade Used in Crystallized Section

Yu, Wang; Jianyi, Yao; Zhijun, Li
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.23%
Turbodrill is a type of hydraulic axial turbomachinery which has a multistage blade consisting of stators and rotors. In this paper, a turbodrill blade that can be applied in crystallized section under high temperature and pressure conditions is developed. On the basis of Euler equations, the law of energy transfer is analyzed and the output characteristics of turbodrill blade are proposed. Moreover, considering the properties of the layer and the bole-hole conditions, the radical size, the geometrical dimension, and the blade profile are optimized. A computational model of a single-stage blade is built on the ANSYS CFD into which the three-dimensional model of turbodrill is input. In light of the distribution law of the pressure and flow field, the functions of the turbodrill blade are improved and optimized. The turbodrill blade optimization model was verified based on laboratory experiments. The results show that the design meets the deep hard rock mineral exploration application and provides good references for further study.

Impact of geometric variability on compressor repeating-stage performance

Vincent, Antoine, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 76 p.; 2548718 bytes; 4370958 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
26.1%
The impact of geometric variability on compressor performance is investigated using a compressor repeating-stage model based on well-known correlations for profile losses, endwall blockage, deviation, and the onset of stall. Previous computations with a quasi-two dimensional cascade analysis code are used to link geometric variability to performance deviations. Performance variability is then introduced probabilistically through random perturbations to tip clearances, profile losses and turning. For the variation input, at design incidence, the mean efficiency is found to decrease by 1%, mostly due to the mean shift in profile losses, and the mean pressure rise is reduced by 2.5%, mostly because of the mean shift in turning. A parametric study for compressor stages of different designs shows a lower degradation of mean performance and a lower performance variability for stages which have higher work coefficient, lower degree of reaction, and higher blade aspect ratio. It was found that the influence of blade profile effects was well represented, but the impact of tip clearance variation was not well captured when compared to three-dimensional computations. It is concluded that to address the effects of tip clearance variability, emphasis should be placed on development of models which both can include the alteration of end-wall displacement thickness within the compressor stage and are appropriate for probabilistic description.; by Antoine Vincent.; Thesis (S.M.)--Massachusetts Institute of Technology...

Probabilistic analysis of meanline compressor rotor performance

Fitzgerald, Nathan Andrew, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 85 p.; 3919038 bytes; 3928267 bytes; application/pdf; application/pdf
EN_US
Relevância na Pesquisa
26.13%
This thesis addresses variability in aerodynamic performance of a compressor rotor due to geometric variation. The performance of the rotor is computed using a meanline model that includes the effect of tip clearance blockage, calculated by assuming the tip leakage behaves like a wake in a pressure gradient and incorporating the effects of double leakage. The model is used to quantify performance variability of the rotor at design flow coefficient and near stall given typical variations in blade profile geometry, hub and casing diameters, and tip clearances. Monte Carlo simulation performed at both operating conditions shows that the coefficient of variation of pressure rise, loss coefficient, axial displacement thickness, and flow angle at the exit of the blade row is similar at high and low loading. Mean shifts are smaller at design than near stall, where the mean pressure rise and loss shift -0.4% and +0.6% from their respective nominal values. A parametric analysis using a response surface showed that near stall, tip clearance variation drives performance variation; the pressure rise and loss coefficient standard deviation drop by 26% and 20% when tip clearance variability is removed. At design, tip clearance variability is still important...

On the miniaturisation of convenction cooling solutions applicable to portable electronic devices

Stafford, Jason
Fonte: University of Limerick Publicador: University of Limerick
Tipo: Doctoral thesis; all_ul_research; ul_published_reviewed; ul_theses_dissertations; none
ENG
Relevância na Pesquisa
16.12%
peer-reviewed; Dimensional restrictions in electronic equipment have resulted in miniaturisation of many existing cooling technologies. In addition, cooling solutions are required to dissipate increased thermal loads to maintain component reliability and user comfort. Fans are widely used in electronics cooling to meet such thermal demands, either in standalone for direct component cooling, or in combination with a heat sink. The thermal performance of such designs when scaled to dimensions suitable for use in portable electronics has received limited attention, mainly due to the reliance on passive cooling methodologies currently employed. However, as heat flux increases, passive cooling is reaching its limit and other solutions will be required. This thesis aims to address this issue by experimentally examining the fluid dynamics and thermal performance of forced convection cooling solutions with dimensional constraints. Conventional finned and novel finless heat sink designs have been integrated with commercially available radial blowers to investigate cooling solutions with overall foot print areas as low as 487mm2, and profile heights less than 5mm. The novel finless geometry, with reduced manufacturing cost, energy consumption and weight promoted heat transfer above that of the same size classical finned designs for a range of operating points. Both geometries showed increases of up to 20% in thermal performance by aligning the fan exit flow with the heat sink channels...

Numerical and experimental analysis of the performance of staggered short pin-fin heat exchangers

Hamilton, Leonard J.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Relevância na Pesquisa
15.87%
Approved for public release, distribution is unlimited; A three dimensional finite element based numerical model was used to analyze the heat transfer characteristics of various staggered short pin-fin array heat exchangers. The simulation was validated against data from an experimental rig as well as historical data and then used to estimate the heat transfer coefficient and pressure drop for a wide range of Reynolds numbers for circular and airfoil-shaped pin fins. Circular pin configuration variations included changes in pin spacing, axial pitch and pin height ratio. Airfoil pin variations also included changes in length and aspect ratio. Correlations for Nusselt number and friction factor were developed. Using established performance metrics, optimum configurations for both pin shapes were determined. The optimum airfoil pin array was shown to match the heat transfer rates obtained by the optimum circular pin configuration while incurring less than one third the specific fluid friction power loss. The results from this study would be of direct value in the design of a shroud enclosed heat exchanger concept being proposed for turbine blade cooling, or for cooling of high power electronic components, or in other high heat flux dissipation applications requiring a low-profile...

Experimental study of the instationary flow between two ducted Counter-rotating rotors

NOURI, Hussain; DANLOS, Amélie; RAVELET, Florent; BAKIR, Farid; SARRAF, Christophe
Fonte: Arts et Métiers ParisTech Publicador: Arts et Métiers ParisTech
EN_US
Relevância na Pesquisa
15.92%
The purpose of this work is to study experimentally the aerodynamic characteristics of a subsonic counter-rotating axial-flow fans system operating in a ducted configuration. The fans of diameter D = 375 mm were designed to match the specification point using an original iterative method: the front rotor blade cascade is designed with a conventional inverse method, setting the radial distribution of the Euler work. The through-flow is then computed using an axisymmetric and radial equilibrium asumption, with empirical models of losses. The rear rotor is not conventional but is designed to straighten the radial profile of the tangential velocity. The design of the front rotor is then modified until the stage meets the requirements. The experimental setup is arranged such that the rotation rate of each fan is independently controlled and that the axial distance between the rotors can be varied from 17% to 310% of the mid-span chord length. Systematic measurements of the global performances and local measurements of the velocity field and of the wall pressure fluctuations are performed, in order to first validate the design method, and to explore the effects of the two specific free parameters of the system: the axial spacing and the ratio of rotation rates. The results show that the efficiency is strongly increased compared to a conventional rotor or to a rotor-stator stage. The developed design method slightly over-predicts the pressure rise and slightly under-predicts the best ratio of rotation rates. Flow angle measurements downstream of the stage show that the outflow is not completely straightened at the design point. Finally...

Influence of Reynolds Number on Multi-Objective Aerodynamic Design of a Wind Turbine Blade

Ge, Mingwei; Fang, Le; Tian, De
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 03/11/2015 EN
Relevância na Pesquisa
26.21%
At present, the radius of wind turbine rotors ranges from several meters to one hundred meters, or even more, which extends Reynolds number of the airfoil profile from the order of 105 to 107. Taking the blade for 3MW wind turbines as an example, the influence of Reynolds number on the aerodynamic design of a wind turbine blade is studied. To make the study more general, two kinds of multi-objective optimization are involved: one is based on the maximum power coefficient (CPopt) and the ultimate load, and the other is based on the ultimate load and the annual energy production (AEP). It is found that under the same configuration, the optimal design has a larger CPopt or AEP (CPopt//AEP) for the same ultimate load, or a smaller load for the same CPopt//AEP at higher Reynolds number. At a certain tip-speed ratio or ultimate load, the blade operating at higher Reynolds number should have a larger chord length and twist angle for the maximum Cpopt//AEP. If a wind turbine blade is designed by using an airfoil database with a mismatched Reynolds number from the actual one, both the load and Cpopt//AEP will be incorrectly estimated to some extent. In some cases, the assessment error attributed to Reynolds number is quite significant, which may bring unexpected risks to the earnings and safety of a wind power project.

Compressor leading edges

Goodhand, Martin
Fonte: University of Cambridge; Department of Engineering Publicador: University of Cambridge; Department of Engineering
Tipo: Thesis; doctoral; PhD
Relevância na Pesquisa
16.02%
Compressor blades often have a small 'spike' in the surface pressure distribution at the leading edge. This may result from blade erosion, manufacture defects or compromises made in the original design process. In this thesis it is shown that these spikes will increase the loss generated by a blade only when they become large enough to initiate boundary layer transition at the leading edge through a separation bubble; this process increases profile loss by about 30%. A criterion is presented, based on the spike diffusion, which can be used to determine whether leading edge transition will occur or not; this criterion is simple and quick to determine and has to potential to be used on a production line to reject those leading edges that would otherwise be detrimental. The spikes are also shown to have a significant effect on the flow close to the endwalls. If they cause leading edge transition in this region then they will cause a growth in the size of the three-dimensional separations that exist in the corner between the blades' suction surfaces and the endwalls. On the low speed stator tested this process increased hub loss by around 100%. Thus to prevent spikes becoming large a new method for producing a 'spikeless' leading edge has been developed; this leading edge can be attached easily to the thickness distribution of any blade and was found to be sharp...

Analytical Investigation of Some Three-Dimensional Flow Problems in Turbomachines

Marble, Frank E.; Michelson, Irving
Fonte: National Advisory Committee for Aeronautics Publicador: National Advisory Committee for Aeronautics
Tipo: Report or Paper; PeerReviewed Formato: application/pdf
Publicado em /03/1952
Relevância na Pesquisa
16.37%
One problem encountered in the theory of turbomachines is that of calculating the fluid velocity components when the inner and outer boundaries of the machine as well as the shape of or forces imparted by the blade row are given. The present paper discusses this problem under the restrictions that the fluid is inviscid and incompressible and that the blade rows consist of an infinite number of infinitely thin blades so that axially symmetric flow is assumed. It is shown, in general, that the velocity components in a plane through the turbomachine axis may be expressed in terms of the angular momentum and the leading-edge blade force normal to the stream surfaces. The relation is a nonlinear differential equation to which analytic solutions may be obtained conveniently only after the introduction of linearizing assumptions. A quite accurate linearization is effected through assuming an approximate shape of the stream surfaces in certain nonlinear terms. The complete linearized solution for the axial turbomachine is given in such form that blade loading, blade shape, distribution of angular momentum, or distribution of total head may be prescribed. Calculations for single blade rows of aspect ratio 2 and 2/3 are given for a radius ratio of 0.6. They indicate that the process of formation of the axial velocity profile may extend both upstream and downstream of a high-aspect-ratio blade row...

On a self-start Darrieus wind turbine: blade design and field tests

Melicio, Rui
Fonte: Renewable and Sustainable Energy Reviews (ELSEVIER) Publicador: Renewable and Sustainable Energy Reviews (ELSEVIER)
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.37%
This paper is about a design of an urban area Darrieus VAWT, having self-start ability due to an innovative profile design named EN0005, avoiding the need of extra components or external electricity feed-in. An approach is presented to study the ability of a blade profile to offer self-start ability. Methodologies applied for the blade body and for profile development are reported. Field tests and main conclusions are presented to persuade for the arrangement of this design.

Innovative design on technology of urban Darrieus VAWT: field tests

Melicio, Rui
Fonte: 16th IEEE International Conference on Computer as a Tool — EUROCON 2015 Publicador: 16th IEEE International Conference on Computer as a Tool — EUROCON 2015
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
55.92%
This paper is about an innovative design for an urban Darrieus Vertical Axis Wind Turbine (VAWT), having the ability of having self-start at low wind velocities, but without the need for extra components or external electricity feed-in. A new mathematical model to assess complex shaped Darrieus VAWT prototype is presented in this paper and offers a new approach to the Double Multiple Streamtube model. Field tests to assess the behavior of the prototype and main conclusions are presented.