Effect of probe size on phase-detection probe measurements of air-water flow properties in hydraulic jumps

This experimental study investigated the air-water flow properties and bubble characteristics in hydraulic jumps with Froude numbers Fr₁ = 2.4 and 6.3, using four dual-tip phase detection probes with sensor sizes from 0.25 mm to 0.64 mm. The hydraulic jumps were characterized by a fully breaking roller with substantial air...

Using CFD to design riprap bed protections downstream of underflow weirs: Weir design of the future

Weirs are constructed inside rivers to manage the water level. On the one hand they need to be designed sufficiently strong to prevent failure or destruction, while on the other hand they need to be economically feasible. If a structure is designed too strong, unnecessary costs are made and the structure becomes too expensive.<br/><br/>One of...

On the Efficiency of Staggered C-Grid Discretization for the Inviscid Shallow Water Equations from the Perspective of Nonstandard Calculus

This paper provides a rationale for the commonly observed numerical efficiency of staggered C-grid discretizations for solving the inviscid shallow water equations. In particular, using the key concepts of nonstandard calculus, we aim to show that the grid staggering of the primitive variables (surface elevation and normal velocity components)...

Two-phase air-water flows in hydraulic jumps at low Froude number: Similarity, scale effects and the need for field observations

A hydraulic jump is a region of rapidly-varied flow that is extremely turbulent. While the one-dimensional continuity and momentum principles have been successfully applied to express the relationships between upstream and downstream conditions, the three-dimensional equations cannot be resolved without some complicated turbulence closure,...

Hydraulic jumps with low inflow Froude numbers: air–water surface patterns and transverse distributions of two-phase flow properties

Abstract: Hydraulic jumps are commonly employed as energy dissipators to guarantee long-term operation of hydraulic structures. A comprehensive and in-depth understanding of their main features is therefore fundamental. In this context, the current study focused on hydraulic jumps with low Froude numbers, i.e. Fr₁ = 2.1 and 2.4, at...

Co-current air-water flow in downward sloping pipes: Transport of capacity reducing gas pockets in wastewater mains

Air-water flow is an undesired condition in many systems for the transportation of water or wastewater. Air in storm water tunnels may get trapped and negatively affect the system. Air pockets in hydropower tunnels or sewers may cause blow-back events and inadmissible pressure spikes. Water pipes and wastewater pressure mains in particular are...

Non-hydrostatic numerical modeling of hydraulic jump over a weir

Weir is the construction widely used in hydraulic engineering. It is very important to investigate the behaviors of the flows over a weir. In general when water streams over a weir it behaves various flow patterns according to different flow conditions. Different flow patterns results in different inference on the water level profile and the...

The Undular Hydraulic Jump: On a numerical method for the computation of flows with curved streamlines

From the theory composed of the method of characteristics and the set of all possible continuous ancillary conditions a closed theory is formed by introducing step functions together with overall mass and momentum conservation equations. However, this representation cannot be called realistic when the jump has the form of the undular hydraulic...