Application of Tesla Valve’s Obstruction Characteristics to Reverse Fluid in Fish Migration

Abstract

More and more activities have caused significant damage to the river environment, among which a typical problem of blocked fish migration is constantly attracting people’s attention. Nowadays, fishways are essential hydraulic facilities to solve such problems. Although a different fishway has a particular blocking effect on the water flow, the flow velocity of the vital positions of fish migration in the fishway could still be relatively high locally, which may pose a certain challenge to the fish migration (the higher flow velocity could lead to the increase in migratory energy consumption of fish). Therefore, further exploration of fish passing facilities may be required. As a check valve without movable parts, the Tesla valve is expected to be used in fish passing facilities because of its substantial obstruction to the reverse flow of internal fluid. This paper conducted numerical simulation experiments on the fish passage pipeline designed based on Tesla valves using the RNG (renormalization group) k-ε model. Grass carp were selected as the primary analysis object, and the simulation results were analyzed from the perspective of turbulence characteristics. The results showed that the fish passage pipeline based on the T45-R Tesla valve was better than that on the GMF (Gamboa, Morris and Forster) Tesla valve in velocity control. The velocity at the vital position of T45-R internal fluid was about 20% lower than that of GMF. The results of the velocity cloud diagram showed apparent high-velocity and low-velocity areas in the fish passage pipeline designed based on the T45-R Tesla valve. The high-velocity area was the vital position for fish upstream, and the maximum velocity variation range in this area was 0.904~1.478 m/s. At the same time, the flow in the low-velocity area is almost static water. The analysis illustrated that the resulting velocity environment could provide conditions for grass carp to move upstream successfully. The results of turbulent kinetic energy inside the fish passage pipeline showed that the maximum value of turbulent kinetic energy was only about 0.043 m2/s2, which could be friendly for fish upstream. In addition, the results show that pressure-related problems could not seem to have an excessive impact on fish migration, such as causing damage. Overall, the results further studied the feasibility of using the Tesla valve as a fish passage pipeline.

Research on the Hydraulic Characteristics of Island Fishways by Experimental and Numerical Methods

“…Standard wall parameters were used for each face. The SIMPLE pressure velocity coupling algorithm (the SIMPLE algorithm, called Semi Implicit Method for Pressure Linked Equations, is a widely used numerical method in computational fluid dynamics for solving the flow field) and second-order upwind scheme were adopted [16,31,35]. The number of iteration steps was set to 2000, the maximum iteration step size was 20, and the convergence error was 10 −4 .…”

“…Hoek et al [15] summarized the former's work and believed that introducing Tesla valves would be beneficial for building FMRs (fish migration rivers). Subsequently, we used numerical simulation to study the application of Tesla valves in fishways [16]. The work studied the internal flow pattern, turbulent kinetic energy, and pressure of Tesla valves as fish-passing pipelines.…”

“…Different studies have taken grass carp as the research object [21,22]. In order to continue previous research, grass carp has often been considered as the main analysis object [16].…”