简介：

简介：在在活动的沙沙丘上的狂暴的液体运动和沉积粒子运动之间的关系被在在USDA-ARS-National沉积实验室执行的实验室实验使用激光Doppler速度计和一个声学的反散射系统调查。当以活动沙丘bedforms的速度下游地翻译两台测量设备时，从粒子和at-a-point骚乱数据的声学的反散射的侧面被收集。产生数据集合被用来检验波动的反散射和液体速度信号基于标准差在超过了大小阀值的频率(复发频率)()本地速度和大小从推迟的粒子源于反散射的声学的信号。下游、垂直的速度复发频率的斜坡通常与增加举起显示了一逐渐地增加的复发时间。为声学的反散射数据的复发频率不与举起是强烈可变的。在在1大小阀值的沉积反散射和垂直速度的复发频率之间的最靠近的通讯被X/L在一个区域定义<0.4并且y<6厘米。下游的速度是最仔细与在在0.4点的一个小区域的反散射有关

简介：Thispaperpresentstheresultsofanexperimentalstudyfocusedonthepropagationofdam-breakflowwavesovermovablebeds.Testsconsistedinthesuddenopeningofaverticallift-gatewhichseparatedinitialwaterandsedimentlevelsupstreamanddownstreamofthegate.Theyallowedthesimulationofthefollowinginitialconditions:withorwithoutinitialbed-stepatthegatecross-section;withorwithoutwaterdownstreamofthegate;withorwithoutsedimentsdownstreamofthegate.Testresultswereusedtodiscusstheinfluenceofthemovablebedonthecelerityofthewave-fronts,aswellasonthedownstreamwave-frontheight.Thetotalvolumeofdislodgedsedimentswasalsoassessed.Someimportantconclusionswereachieved:i)themovablebeddoesnotaffecttheupstreamwave-frontceleritybutitaffectsthecelerityofthedownstreamwave-front;ii)theexperimentalceleritiesshowsomedisagreementwiththeanalyticalsolutions;iii)theexistenceofaninitialbed-stepatthelift-gatecross-sectioninfluencesthedownstreamwave-frontpropagation,includingthewaterdepth.

简介：深度有限的实验室实验在一张石子床上的开隧道的流动在学习被进行。有相同单个元素尺寸和不同长度(3.81m和7.5m)的二个石子补丁被测试。有亲戚的深度有限制服流动政体浸没Sr(=D/k从2.68～5.94的s)被调整尾板堰生产。速度侧面被使用一个超声速度剖析程序(UVP)和声学的Doppler速度计(副词)测量。过去常决定零飞机的排水量并且估计床的常规方法砍速度然后被考察并且比较。测量双averaged(DA)速度侧面被发现与一个非通用的Karman常数与木头法律和缺点法律适合很好。将近经常的价值遗体并且在为长补丁(LP)的从0.2～0.3的范围，盒子和价值为短补丁(SP)从0.3～0.5在一个更宽的范围以内被散布盒子。当在木头法律的Br值为LP诉讼仍然保持对8.5不变、相等时，Br值被发现随无尺寸的粗糙高度k为SP诉讼的s+。streamwise骚乱紧张分布被发现在补丁长度上独立并且在中间的区域和墙区域与可得到的试验性的数据同意很好。曼宁抵抗系数和DarcyWeisbach磨擦因素被分析。为在小亲戚下面的对数的流动抵抗法律的试穿的到0.22的价值减少浸没。在对数的法律的集成常数Ar的价值在在3.25和6.25之间的正常范围以内掉落。

简介：Therelationbetweengrain-sizedistributionofthebedandinsuspensionwascriticallyexaminedunderauniformflowvelocityof50cm/sovertwobeds:oneofmainlyfinesandsandtheotherofmediumsands.Twosections-one2.85mdownstreamandtheother6.35mdownstreamintheexperimentalchannel-wereselectedforsamplingtostudythegrain-sortingpatternintheverticaldirectionalongthedirectionoftransport.Theshapeandtypeofthegrain-sizedistributionpatternwerecriticallystudiedwithheightabovethebed.Thechangeinthedistributionpatternhasbeenattributedtothechangeoflocalbedroughnesscausingscouringagainsttheprotrudedrelativelycoarsegrainsonthebed.Suchtrendsareimportanttopredictthenatureofriverbedtopography.ThesandofBed-1initiallyexhibitsalog-skew-Laplacedistributionatdifferentheightsofsuspension.Thedistributionpattern,however,changesbutthischangingpatternisnotconsistentalongtheupstreamside.ForBed-2,whichinitiallyexhibitsalog-normaldistribution,thesamepatternpersistsfromtheheightofsuspensionat5cmupto20cm.Suchconsistencyinlog-normalityisalsoobservedatthedownstreampointsofmeasurement.Itisgenerallyexpectedthatthemeangrain-sizewouldreducewithincreasesofsuspensionheightbuttheresultsoftheexperiments,insomeoccasions,differsignificantlyfromthegradualfiningupwardtrend.Thisresulthasbeenattributedtolocalchangesofbedroughnessarisingfromtheprotrudedrelativelycoarsegrainscausingeddies,scouring,andturbulentphenomenawhichmovescoarseparticleshigherinsuspensionaddingacoarsetailtothedistributionincreasingthemeangrain-size.

简介：这份报纸调查狂暴的爆炸事件的现象，并且由固定长度的短圆形的柱体发展了在scour几何学在事件之中做比较研究，不同直径放了在对流动横向的沙床上。狂暴的动能(TKE)的分布，在在不同地点的纵、垂直的方向的狂暴的散开搜索标记，并且到雷纳兹的爆炸打扫周期的贡献砍应力被介绍。