水利学报
水利學報
수리학보
2014年
11期
1310-1317
,共8页
综合糙率%冰盖%明渠%流速分布
綜閤糙率%冰蓋%明渠%流速分佈
종합조솔%빙개%명거%류속분포
generalized formula%composite roughness%ice cover%open channel and distribution of water velocity
明渠冰盖下流动的综合糙率 nc是确定冰期水位和流量关系的关键参数,本文根据冰盖区和床面区的边界条件和流量的连续性条件提出了通用的综合糙率公式,研究了冰盖下一般矩形明渠和宽浅明渠流速分布及流速比a对综合糙率 nc的影响,在此基础上,计算分析比较了通用综合糙率公式、Einstein公式、Belokon-Sabaneev公式和 Larsen公式的差异和使用条件,结果表明:对于宽深比 b/H较小的矩形明渠,采用 Belokon-Sabaneev公式将产生很大的计算偏差, Larsen公式只适合宽浅明渠,而Einstein公式是通用综合糙率公式的最好近似,推荐在工程设计中采用。
明渠冰蓋下流動的綜閤糙率 nc是確定冰期水位和流量關繫的關鍵參數,本文根據冰蓋區和床麵區的邊界條件和流量的連續性條件提齣瞭通用的綜閤糙率公式,研究瞭冰蓋下一般矩形明渠和寬淺明渠流速分佈及流速比a對綜閤糙率 nc的影響,在此基礎上,計算分析比較瞭通用綜閤糙率公式、Einstein公式、Belokon-Sabaneev公式和 Larsen公式的差異和使用條件,結果錶明:對于寬深比 b/H較小的矩形明渠,採用 Belokon-Sabaneev公式將產生很大的計算偏差, Larsen公式隻適閤寬淺明渠,而Einstein公式是通用綜閤糙率公式的最好近似,推薦在工程設計中採用。
명거빙개하류동적종합조솔 nc시학정빙기수위화류량관계적관건삼수,본문근거빙개구화상면구적변계조건화류량적련속성조건제출료통용적종합조솔공식,연구료빙개하일반구형명거화관천명거류속분포급류속비a대종합조솔 nc적영향,재차기출상,계산분석비교료통용종합조솔공식、Einstein공식、Belokon-Sabaneev공식화 Larsen공식적차이화사용조건,결과표명:대우관심비 b/H교소적구형명거,채용 Belokon-Sabaneev공식장산생흔대적계산편차, Larsen공식지괄합관천명거,이Einstein공식시통용종합조솔공식적최호근사,추천재공정설계중채용。
The composite roughness of the ice covered flow is a key parameter to determine the relation?ship between the flow and water stage. This paper presents a generalized formula for the composite rough?ness of ice covered flows by analyzing the relationship among Manning roughness, section-averaged water velocity and wetted perimeter. Based on the generalized formula, the influence of the velocity coefficient a on the composite roughness of the ice covered flows in rectangular channels is studied by considering the distribution of water velocities. Meanwhile, in order to understand the scope of application to them, Ein?stein formula, Belokon - Sabaneev formula and Larsen formula are compared with the generalized formula systematically. The results show that for the rectangular open channal with small kreadth-depth ratio b/H, the composite roughness computed by Einstein formula approximate closest to that by the generalized formu?la, and the composite roughness obtained by both Belokon- Sabaneev formula and Larsen formula deviate for from that by the generalized formula in many cases.