EAGER: Development of a High-Control Jet-Array Wavemaker

尽管最近在数值模拟方面取得了进展，但仍然需要在控制良好的实验室环境中用机械产生的波来研究许多波现象。传统上，并且几乎普遍地，波浪在具有在流体柱中机械振荡的移动活塞或翻板的罐中产生。这些系统的好处是相对简单，用户经验和知识基础广泛。缺点主要在于物理限制;特定设计的造波机针对特定的波浪状态，例如长或短，线性或非线性。此外，对于这些传统的造波机系统，耦合的波和流，甚至进一步的分层，开始需要拼凑的修改，并且可能不适合于基础科学研究。这一探索性项目将开发和实施一个新的实验概念，使用一系列计算机控制的水射流进行“完整”的波浪、水流和分层控制。 这有可能从根本上改变科学家和工程师研究海洋流动的方式。使用这种技术的小型坦克，如本项目中将要建造的坦克，相对便宜，广泛推广这一概念是一个目标。开发的设计图纸和控制系统配置将完全开放，并通过在线方式分发。 在未来的某个时候，波和流设施可能会完全取消墙壁和造波机，取而代之的是用蜂窝状的流入口包裹在所有侧面，所有这些都是单独和同时控制的。为了解决多尺度和多流体物理问题，需要一个新的实验平台来研究复杂的海洋情况。这个“平台”被称为喷气阵列造波机（JAW），旨在用一系列单独的流动系统取代传统的造波机概念，每个系统都将气流输送到特定的垂直高度。流量输送方法由一个充满水的气缸和一个马达控制的活塞组成，活塞将水从气缸中推出和拉入气缸。该系统具有非常精确的流量控制，因为电机可以接受非常高频率的输入，并可以提供足够的扭矩，以合理的成本满足大多数需求。来自气缸的流率是直接控制的，因为它是一个简单的质量守恒计算。由于活塞的位移与电机转数的时间积分线性相关，因此钳口同样精确。因此，气缸概念在精度和控制方面明显优于其他系统，这是JAW系统最重要的组成部分。与现有造波机系统相比，JAW有两个主要的物理应用空间优势。第一个是波数乘以深度的应用范围非常广;可以同时运行波和电流，其中这两个分量通过同一系统生成。JAW系统的第二个主要优点是同时产生波浪、海流和分层流，包括内波。这是该系统最独特的潜力，并应提供机会，研究复杂的海洋学过程，这是无法接近现有的系统。

Despite recent advances in numerical modeling, there is still a need to study many wave phenomena in a well-controlled laboratory setting with mechanically generated waves. Traditionally, and nearly universally, waves are generated in a tank with a moving piston or flap that is mechanically oscillated in a column of fluid. The benefits of these systems are their relative simplicity and a large base of user experience and knowledge. Drawbacks lie mainly in physical limitations; a wavemaker of a certain design targets a specific regime of waves, such as long or short, linear or nonlinear. Further, with these traditional wavemaker systems, coupled waves and currents, and even further stratification, begin to require a patchwork of modifications and may not be suitable for fundamental scientific investigation. This exploratory project will develop and implement a new experimental concept for "complete" wave, current, and stratification control using an array of computer-controlled water jets. This has the potential to fundamentally change the way scientists and engineers study oceanographic flows. Small-scale tanks using this technology, such as the one to be built in this project, are relatively inexpensive, and widespread proliferation of the concept is a goal. The developed design drawings and control system configuration will be completely open and distributed through online means. At some future time, wave and flow facilities may do away with walls and wavemakers completely, being instead wrapped on all sides with a honeycomb of flow portals, all individually and simultaneously controlled. In order to attack multi-scale and multi-fluid physics problems, a new experimental platform to study complex oceanographic situations is required. This "platform", called the jet-array wavemaker (JAW), is meant to replace the traditional concept of a wavemaker, simplistic in its bulk, with a series of individual flow systems, each delivering flow to a specific vertical level. The flow delivery method consists of a water-filled cylinder with a motor-controlled piston pushing and pulling water out of and into the cylinder. This system has extremely precise flow control, as the motors can accept input at very high frequencies and can deliver enough torque to meet most needs at reasonable cost. The flow rate from the cylinder is straightforward to control as it is a simple conservation-of-mass calculation. The JAW is similarly precise as the displacement of the piston is linearly correlated to the time-integration of the motor revolution count. Thus, the cylinder concept has clear advantages over other systems in terms of precision and control, which are the most important components of a JAW system. There are two primary physical-application-space advantages of the JAW over existing wavemaker systems. The first is the very wide range of wavenumber times depth application; one can run simultaneous waves and currents where these two components are generated through the same system. The second primary advantage of the JAW system is the generation of simultaneous waves, currents, and stratified flow, including internal waves. This is the most unique potential of the system, and should present opportunities to study complex oceanographic processes which are unapproachable with existing systems.