MARITIME – PORT, HARBOUR & CHANNEL OPERATION CALCULATOR
Harbour Resonance
A precise tool.
What is the Harbour Resonance & How does it work?
Harbour resonance, also known as a seiche, occurs when the natural oscillation period of a water body aligns with external forcing such as wind or atmospheric pressure. In a rectangular basin the dominant mode is a standing wave that sloshes back and forth between the two ends.
The period of this oscillation depends primarily on the geometry of the basin and the speed at which gravity waves travel through the water column. For a basin of length L and uniform depth h, the wave speed is sqrt{g,h}, where g is the acceleration due to gravity.
Combining the wave speed with the condition that a full oscillation requires a wave to travel the length of the basin twice yields the classic resonance period formula shown below.
T = frac{2L}{sqrt{g h}}
T = resonance period (s), L = basin length (m), g = gravitational acceleration (m/s²), h = average depth (m)
Parameters
Result
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Frequently Asked Questions
What is harbour resonance?
Harbour resonance, or seiche, occurs when a water body's natural oscillation period matches external forces like wind or atmospheric pressure.
How does the wave speed in a rectangular basin affect the oscillation period?
The wave speed in a rectangular basin is calculated as sqrt(g*h), where g is the acceleration due to gravity and h is the depth of the water. This affects the period of oscillation.
What factors determine the dominant mode of oscillation in a rectangular basin?
The dominant mode of oscillation in a rectangular basin is primarily determined by the geometry of the basin, specifically its length and depth.
How does the length of the basin affect the oscillation period?
The longer the basin, the longer the natural oscillation period. This is because it takes more time for a wave to travel back and forth between the two ends.
What is the formula for calculating the wave speed in a rectangular basin?
The wave speed is calculated using the formula sqrt(g*h), where g is the acceleration due to gravity and h is the depth of the water.
Can external forces like wind or atmospheric pressure cause harbour resonance?
Yes, when the natural oscillation period of a water body aligns with external forces such as wind or atmospheric pressure, it can cause harbour resonance.
What is the significance of the dominant mode in a rectangular basin?
The dominant mode is significant because it represents the primary way that energy is stored and transferred within the water body, often manifesting as a standing wave between the two ends of the basin.
Results are for informational purposes only and do not constitute professional advice.