What angle of stack offset is generally considered to potentially cause hydraulic jump?

A stack offset at a 45-degree angle is generally considered to potentially cause hydraulic jump due to the dynamics of fluid flow within the plumbing system. At this angle, the flow transitions from vertical to horizontal, which can result in changes in velocity and pressure. When fluid enters a different elevation or direction abruptly, as it does at this angle, it can lead to turbulence, which is the primary contributor to a hydraulic jump.

A hydraulic jump occurs due to the sudden change in flow regime from a supercritical flow (fast-moving) to a subcritical flow (slower moving), which can create significant turbulence and energy loss within the system. This is especially relevant in stack systems where the flow must be efficient to ensure proper drainage and to prevent blockages or backflow issues.

While other angles like 30 degrees or 60 degrees may affect flow, they typically do not generate the same level of turbulence or disruption as a 45-degree offset. A 90-degree angle, while causing a significant change in direction, is often associated with fittings that have larger radiuses to mitigate abrupt changes in flow, limiting the potential for hydraulic jumps. Thus, the 45-degree angle is a critical consideration in plumbing design to maintain smooth, efficient flow and avoid hydraulic disturbances