导流板改善弯管流场的数值模拟与优化   总被引：1，自引：0，他引：1  

贾兴豪  彭向和  龙血松 《西南大学学报(自然科学版)》2011,33(3)

为改善弯管内因流体不规则流动造成的管道振动,提高管道工作的可靠性,通过在弯管内部按照等比例方案加装不同结构形式的导流器,使用RNGk-ε模型计算模拟了弯管内流体的流动特性.结果表明:在弯管内部特定位置加装导流器能显著地改善弯管内流体的流动.  相似文献   

Instrument breakage as a complication of elbow arthroscopy in a dog     

JG Grand  JA Roig  M de Swarte 《Australian veterinary journal》2014,92(4):128-131

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Hyperostotic bone disease in a wombat (Vombatus ursinus)     

V. Slon  D. Stein  H. Cohen  B. Medlej  N. Peled  I. Hershkovitz 《Research in veterinary science》2014

Little is known about wombat diseases in general, and about their congenital diseases in particular. In the current study, the skeleton of a common wombat (Vombatus ursinus) that exhibited generalized hyperostosis is analyzed, and possible diagnoses are reviewed. Macromorphological analyses revealed that the diaphyses of the long bones manifested an increased diameter with extensive diaphyseal new-bone formation (periosteal and endosteal). Cross-sections of the diaphyses showed that the cortical–medullary demarcation was indistinct. The calvarial bones were thickened. Radiographs showed uniform sclerosis of the long bones with loss of trabecular pattern. Microradiography showed extensive bone remodeling, a hyper-vascularized lamellated layer of bone and numerous linear formation defects. Possible causes for the lesions, including sclerosing bone dysplasia disorders, acquired syndromes causing hyperostosis, and metabolic diseases typical of animals in captivity, are discussed.  相似文献   

Prevalence and co-occurrence of hip dysplasia and elbow dysplasia in Dutch pure-bred dogs     

I.C.M. Lavrijsen  H.C.M. Heuven  B.P. Meij  L.F.H. Theyse  R.C. Nap  P.A.J. Leegwater  H.A.W. Hazewinkel 《Preventive veterinary medicine》2014

Hip as well as elbow dysplasia (HD, ED) are developmental disorders leading to malformation of their respective joints. For a long time both disorders have been scored and targeted for improvement using selective breeding in several Dutch dog populations. In this paper all scores for both HD and ED, given to pure bred dogs in the Netherlands from 2002 to 2010, were analyzed. Heritabilities and correlations between HD and ED were calculated for the 4 most frequently scored breeds. Heritabilities ranged from 0.0 to 0.37 for HD related traits (FCI-score, osteoarthritis, congruity, shape and laxity (Norberg angle); FCI: Fédération Cynologique Internationale) and from 0.0 to 0.39 for ED related traits (IEWG score, osteoarthritis, sclerosis and indentation; IEWG: International Elbow Working Group). HD related traits showed high genetic and residual correlations among each other but were only to a minor extent correlated with ED related traits, which also showed high correlations among each other. Genetic correlations were higher than residual correlations. Phenotypic and genetic trends since 2001 for the four most scored breeds were slightly positive but decreasing over time, indicating that selection over the past decade has not been effective.  相似文献   

A Study on the Algorithm of Draft-Tube in Computer Graphs Treatment     

DU Ting-na 《保鲜与加工》2003,(1):86-89

The geometrical characteristics of high-narrow-type draft tube are analyzed. The algorithm is designed as having the projection before seeking its envelope. A series of detailed graphs are drawn. An excellent condition is created for construction of high-narrow-type draft tube.  相似文献   

COMPARISON OF CLINICAL, RADIOGRAPHIC, COMPUTED TOMOGRAPHIC, AND MAGNETIC RESONANCE IMAGING METHODS FOR EARLY PREDICTION OF CANINE HIP LAXITY AND DYSPLASIA     

MÁRIO M. D. GINJA  ANTÓNIO J. FERREIRA  SANDRA S. JESUS  PEDRO MELO-PINTO  JOSÉ BULAS-CRUZ  MARIA A. ORDEN  FIDEL SAN-ROMAN  MARIA P. LLORENS-PENA  JOSÉ M. GONZALO-ORDEN 《Veterinary radiology & ultrasound》2009,50(2):135-143

The purpose of the study was to use two palpation methods (Bardens and Ortolani), a radiographic distraction view, three computed tomography (CT) measurements (dorsolateral subluxation score, the lateral center-edge angle, and acetabular ventroversion angle) and two magnetic resonance (MR) imaging hip studies (synovial fluid and acetabular depth indices) in the early monitoring of hip morphology and laxity in 7–9 week old puppies; and in a follow-up study to compare their accuracy in predicting later hip laxity and dysplasia. The MR imaging study was performed with the dog in dorsal recumbency and the CT study with the animal in a weight-bearing position. There was no association between clinical laxity with later hip laxity or dysplasia. The dorsolateral subluxation score and the lateral center-edge angle were characterized by a weak negative correlation with later radiographic passive hip laxity (−0.26< r <−0.38, P <0.05) but its association with hip dysplasia was not significant. There was an association between early radiographic passive hip laxity and synovial fluid index with later passive hip laxity (0.41< r <0.55, P <0.05) and this was significantly different in dysplastic vs. nondysplastic hips ( P <0.05). There was no association between the remaining variables and later hip laxity or dysplasia. The overlapping ranges of early passive hip laxity and synovial fluid index for hip dysplasia grades and the moderate correlations with the later passive hip laxity make the results of these variables unreliable for use in predicting hip laxity and dysplasia susceptibility.  相似文献   

弯管安装角对管道泵内压力脉动影响的数值研究     

王业富  王洋  宋建龙  金实斌  公续然  朱芮  曹璞钰 《排灌机械工程学报》2022,40(12):1219-1226

为了深入探究进流弯管与蜗壳相对周向位置对离心泵内水力激振的影响及其流动机理,选取立式管道离心泵为研究对象,通过对原型泵进水弯管周向安装角度的调整,衍生出6组新管道泵,并依次进行非定常数值计算.在数值计算过程中,主体监测叶轮域内压力脉动,对比分析6款新泵与原型泵的压力脉动特征,结果表明:在叶轮进口流域,当周向安装角φ=45°时,压力脉动在时域上产生了较明显的波峰相位提前,与二次流涡对激励的波谷有相互抵消作用,削弱波峰,最大降幅可达40.6%.在叶轮中段流域,安装角φ对叶片背面的压力脉动影响较大.在叶片尾缘附近流域,不同弯管安装角产生的影响沿流道从叶轮进口至叶片尾缘逐渐减小殆尽.本研究可为管道泵的实际安装及优化提供一定的参考.  相似文献