Method for deducing flow velocity distribution under ice sheet

Abstract

The invention relates to a method for deducing the flow velocity distribution under an ice sheet. The method for deducing the flow velocity distribution under the ice sheet comprises the following steps: selecting a measurement section of a typical river channel; selecting time points for recording the measurement section; recording a measurement section status; obtaining flow velocity distribution data; calibrating parameters: taking the flow velocity of each measurement period into the formula; deducing the flow velocity and flow distribution; and accumulating data constantly. According to the method for deducing the flow velocity distribution under the ice sheet, a comprehensive measurement is performed by combining climatic conditions, ice sheet characteristics, and ice freezing stateon a typical river channel, and a number of parameters required for calculations related to the conditions are calibrated through a flow velocity expression. In the freezing period of each subsequentyear, only the climatic conditions, the ice sheet characteristics and the ice freezing state need to be compared to find the corresponding calculation parameters, so that the same flow velocity expression can be used for obtaining the velocity distribution under the ice sheet, and the digging of the ice surface is not required; therefore, the situation that the flow velocity is not consistent withactual flow conditions caused by artificially dividing the sub-ice flow velocity into the ice sheet area and the river bed area is solved.

Description

technical field

[0001] 本发明涉及一种冰盖下流速分布的推演方法,是一种防灾减灾水工调控的计算方法,是一种河渠水流控制和调节的重要参数的计算方法。 Background technique

[0002] 冬天封冻季节来临时,河道或者调水明渠中会形成冰盖。冰盖的存在明显影响水流流动特性,导致河道阻力增加,过流能力下降,流速分布规律发生变化。对于天然河道无法准确的知道流速和流量将导致无法准确的预计可能出现的冰情灾害,影响防灾减灾的效果。对于调水渠道,不了解水渠中冰盖下的水流流速就无法准确进行冬季结冰条件下调水渠道的安全运行调度,对调水渠道的运行产生不利影响。

[0003] 现有的方式是,在冰封季节,人工在冰面上开凿孔洞,使用流速测量仪器对冰盖下的水流进行直接测量。由于这种测量通常在严冬季节进行,由于需要开凿过个孔洞,并进行许多次的测量,科研人员的劳动强度极大,另一方面在流冰或冰塞的情况下,冰面情况复杂,有时根本无法测量。 Contents of the invention

[0004] 为了克服现有技术的问题,本发明提出了一种冰盖下流速分布的推演方法。所的方法通过对冰封期的冰面的观察和测量,率定若干组数据,在之后的冬季用这些数据进行对比,精确推演冰面下的流速,减少了开凿冰面的劳动强度,提高了工作效率。

[0005] 本发明的目的是这样实现的:一种冰盖下流速分布的推演方法,所述方法的步骤如下:

[0006] 步骤1,选择典型河道的测量断面:选择主流河道设置测量断面;对于自然河道则选择在水文站附近,河床形状相对规则,比降适中,水流相对平稳的位置;对于引水渠道则选择在控制闸门和分水口一定距离的位置;测量断面选定后记录测量断面的河床状态,包括:是否为砂石河床、有植被河床、混凝土衬砌河床;根据已有水文资料,将测量断面的水位分为低水位、中水位和高水位;

[0007] 步骤2,选择记录测量断面的时间点:

[0008] 将冰期全过程分为流冰期、封冻期和开河期,将封冻期过程分为初封期、稳封期和开河前期:将测量断面的封冻30%、50%、60%、80%作为河道未完全封冻的测量时段;测量断面的初封期测量时间间隔不大于2天,稳封期的测量时间间隔不大于7天,开河前期的测量时间间隔不大于2天;根据冰面具体变化情况或适当...

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