Laboratory experiments of forming and deepening of set of small individual volumes with negative buoyancy

A database gives photo-recordings of laboratory experiments of deepening of large number of small volumes with negative buoyancy (4-8 ml) with negative buoyancy in freshwater environment. The density difference between the fresh water in the hydroflume and the volumes with negative buoyancy (with salt and dye) was 2*10^-5 g/cm^3 – 10^-4 g/cm^3. Two modes were used to record the process of deepening of volumes: on a Baumer high-speed video camera with a frequency of 10 Hz (400 frames), and also on a Sony-58α digital camera with a frame rate of 1.78 Hz (the number of frames was not fixed). Default Baumer camera settings: exp.time 4000 µ/sec, gain 1 db. The folder [0_special_devices] shows the "window" type input device used in the experiments with a single abrasive sponge (0.4 cm) for the formation of large number of small volumes of with negative buoyancy. To form the second flow group (folder 2), two abrasive sponges (total thickness 0.8 cm) were used. Folder [1_rain_single_h] contains two series of formation and deepening of large number of small volumes with negative buoyancy with a near-surface boundary layer thickness of 0.4 cm. Folder [2_rain_double_h] contains two series of formation and deepening of large number of small volumes with negative buoyancy with a near-surface boundary layer thickness of 0.8 cm.本数据库收录了淡水环境中大量负浮力小体积体（体积为4-8 mL）下沉过程的实验室实验影像记录。实验所用水槽内淡水与搭载盐类和染料的负浮力小体积体之间的密度差为2×10^-5 g/cm³ 至 10^-4 g/cm³。 本次实验采用两种方式记录小体积体的下沉过程：其一为使用Baumer高速摄像机（high-speed video camera），拍摄帧率为10 Hz，总帧数400帧；其二为使用Sony-58α数码相机，拍摄帧率为1.78 Hz，总帧数未固定。Baumer摄像机默认参数如下：曝光时长4000 μs，增益1 dB。 文件夹[0_special_devices]展示了实验所用的“窗口”式输入装置，该装置搭配单层磨料海绵（abrasive sponge，厚度0.4 cm），用于生成大量负浮力小体积体。为生成第二组流体试样，实验采用双层磨料海绵（总厚度0.8 cm），对应文件夹[2_rain_double_h]。 文件夹[1_rain_single_h]包含两组实验，内容为近地表边界层厚度0.4 cm条件下，大量负浮力小体积体的生成与下沉过程。 文件夹[2_rain_double_h]包含两组实验，内容为近地表边界层厚度0.8 cm条件下，大量负浮力小体积体的生成与下沉过程。