Visual Testing (VT) Practice Exam

What is the term for the formation and collapse of gas bubbles in fluids?

1. Water hammer

2. Corrosion

3. Cavitation

4. Erosion

The correct answer is: Cavitation

The process referred to in the question, which involves the formation and collapse of gas bubbles within fluids, is known as cavitation. This phenomenon typically occurs in scenarios where there are rapid changes in pressure within a fluid, leading to the creation of vapor-filled cavities or bubbles. These bubbles can subsequently collapse violently, producing shock waves and potentially causing damage to surfaces—such as in propellers or pump components. Cavitation is significant in various engineering applications, particularly in hydraulic systems and pumps, where it can greatly affect performance and longevity. Understanding cavitation is crucial when designing systems that will be exposed to varying pressure conditions. The other terms mentioned relate to different concepts. Water hammer refers to the pressure surge that occurs when a fluid in motion is forced to stop or change direction suddenly. Corrosion describes the gradual destruction of materials, usually metals, through chemical reactions with their environment. Erosion involves the wearing away of material, often due to mechanical forces like wind or water flow. Each of these processes has distinct mechanisms and implications, but cavitation specifically focuses on the dynamic behavior of gas bubbles within liquids and their effects on surrounding structures.