水利学报
水利學報
수리학보
2013年
7期
800-809
,共10页
马爱兴%陆永军%陆彦%黄廷杰
馬愛興%陸永軍%陸彥%黃廷傑
마애흥%륙영군%륙언%황정걸
非恒定流%非恒定强度参数%砾石推移质%输移特性%水槽试验
非恆定流%非恆定彊度參數%礫石推移質%輸移特性%水槽試驗
비항정류%비항정강도삼수%력석추이질%수이특성%수조시험
unsteady flow%unsteadiness parameter%gravel bed-load%transport characteristics%flume experi-ment
基于水深与流量的变化率提出了反映水流非恒定强度的无量纲参数P。利用水槽非恒定流输沙同步测试系统试验研究了非恒定流作用下砾石推移质的输移特性。试验资料分析表明,非恒定流作用下的砾石推移质输移具有明显的随机性、间歇性与阵发性。水流的非恒定性对输沙率峰值的脉动性有影响,对P>0.32的强非恒定流而言,若输沙率样本数少于20,将会给输沙率结果带来较大的偏差。非恒定流作用下输沙率与水流要素变化具有不同步性,并与水流非恒定强度有关。P>0.32时,输沙率峰值一般滞后于流速峰值;当P<0.32时,可能出现输沙率峰值先于流速峰值的现象。非恒定流作用下砾石推移质平均单宽输沙率(或输沙量)与单宽流量(或径流量)、非恒定强度参数P有关,随P的增强而加大。
基于水深與流量的變化率提齣瞭反映水流非恆定彊度的無量綱參數P。利用水槽非恆定流輸沙同步測試繫統試驗研究瞭非恆定流作用下礫石推移質的輸移特性。試驗資料分析錶明,非恆定流作用下的礫石推移質輸移具有明顯的隨機性、間歇性與陣髮性。水流的非恆定性對輸沙率峰值的脈動性有影響,對P>0.32的彊非恆定流而言,若輸沙率樣本數少于20,將會給輸沙率結果帶來較大的偏差。非恆定流作用下輸沙率與水流要素變化具有不同步性,併與水流非恆定彊度有關。P>0.32時,輸沙率峰值一般滯後于流速峰值;噹P<0.32時,可能齣現輸沙率峰值先于流速峰值的現象。非恆定流作用下礫石推移質平均單寬輸沙率(或輸沙量)與單寬流量(或徑流量)、非恆定彊度參數P有關,隨P的增彊而加大。
기우수심여류량적변화솔제출료반영수류비항정강도적무량강삼수P。이용수조비항정류수사동보측시계통시험연구료비항정류작용하력석추이질적수이특성。시험자료분석표명,비항정류작용하적력석추이질수이구유명현적수궤성、간헐성여진발성。수류적비항정성대수사솔봉치적맥동성유영향,대P>0.32적강비항정류이언,약수사솔양본수소우20,장회급수사솔결과대래교대적편차。비항정류작용하수사솔여수류요소변화구유불동보성,병여수류비항정강도유관。P>0.32시,수사솔봉치일반체후우류속봉치;당P<0.32시,가능출현수사솔봉치선우류속봉치적현상。비항정류작용하력석추이질평균단관수사솔(혹수사량)여단관류량(혹경류량)、비항정강도삼수P유관,수P적증강이가대。
Based on the change rate of water depth and discharge, dimensionless parameter P reflecting the unsteadiness of unsteady flow has been proposed. The gravel bed-load transport in unsteady flow was ex-perimentally investigated with the synchronous test system of unsteady flow sediment transport. Test data analysis shows that bed-load transport under unsteady flow displays randomicity, intermittency and parox-ysm. Unsteadiness has effects on pulsation of peak for sediment transport rate. In the case of unsteady flow with strong unsteadiness,i.e. P>0.32,if samples of sediment transport rate are less than 20,the outcome will be deviated. The variation of sediment transport rate under unsteady flow does not synchronize with flow condition,and also relates to unsteadiness. When P>0.32,the peak of sediment transport rate usually lags behind the peak of flow velocity;while P<0.32, the peak of sediment transport rate perhaps occurs before the peak of flow velocity. Bed-load average transport rate (or bed-load yield) in unsteady flow is re-lated to discharge per unit width (or runoff) and unsteadiness parameter P,and increases as P strengthens.