Hydrology and Earth System Sciences Discussions on the Measurement of Solute Concentrations in 2-d Flow Tank Experiments
Hydrology and Earth System Sciences Discussions on the Measurement of Solute Concentrations in 2-d Flow Tank Experiments
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通讯作者：
M. Konz;P. Ackerer;E. Meier;P. Huggenberger;E. Zechner;D. Gechter
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作者：
M. Konz;P. Ackerer;E. Meier;P. Huggenberger;E. Zechner;D. Gechter
在这项研究中，我们描述并比较了在多孔介质流动槽实验中确定溶质浓度的光度和电阻率测量方法。第一种方法是光度法，它直接将示踪染料的数字测量强度与浓度联系起来，而不需要事先将强度转换为光学密度。这使得能够有效地处理大量图像，以计算流槽不同点处的浓度时间序列。对测量的扰动进行了研究，发现透镜光斑效应和图像分辨率都是主要的误差来源。附加的遮罩能够将镜头光斑效果降至最低。在多孔介质实验中现场测量盐分浓度的第二种方法是电阻率法。该电阻率测量系统在镀金电极棒上使用两个不同的输入电压，可以测量0到300g/L的盐浓度。然而，由于电极的测量体积未知，我们认为图像分析方法更适合于中等规模的实验室基准实验来评估数字代码。
Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract In this study we describe and compare photometric and resistivity measurement methodologies to determine solute concentrations in porous media flow tank experiments. The first method is the photometric method, which directly relates digitally measured intensities of a tracer dye to concentrations without previously converting 5 the intensities to optical densities. This enables an effective processing of a large amount of images to compute concentration time series at various points of the flow tank. Perturbations of the measurements are investigated and both lens flare effects and the image resolution turned out to be the major sources of error. An attached mask is able to minimize the lens flare effects. The second method for in situ measure-10 ment of salt concentrations in porous media experiments is the resistivity method. The resistivity measurement system uses two different input voltages at gilded electrode sticks to enable the measurement of salt concentrations from 0 to 300 g/l. Power laws are used to relate apparent resistivity values and salt concentrations. However, due to the unknown measurement volume of the electrodes, we consider the image analysis 15 method more appropriate for intermediate scale laboratory benchmark experiments to evaluate numerical codes.