Chapter 3
A Conventional Experimental Technique:
Rainfall Simulation
Abstract Rainfall simulation is widely used for the experimental study on soil
and water conservation. This chapter reviews the characteristics, application, and
prospect of rainfall simulator. The rainfall simulators could be divided into two main
groups: the non-pressurized rainfall simulators, including the thread droppers and the
needle droppers, and the pressurized water rainfall simulators, including the spout
and the sprayer. The former could be hardly found at present due to its drawback that
the minimum size of drop produced is far larger and more even than most natural
rainfall and the simulator could not easily generate rains with the similar energy to
the natural one. Rainfall simulation halls with automatic operation and observation
systems are booming in recent years, but the basic simulators will not be completely
replaced in virtue of the cheap price and convenient manipulations.
Keywords Rainfall simulator · Soil erosion · Research advance
3.1 Methods for Simulating the Rainfall
Rainfall is one of the major factors causing hydraulic erosions. However, natural
rainfall experiments might require a considerable amount of time to complete. In
contrast, not only various rainfall intensities may be obtained, but also shorter durations may be permitted in experiments under simulated rainfalls. Moreover, it is
relatively easy to strictly control the experimental conditions and precisely monitor the processes of soil erosion in a rainfall simulation experiment. Especially for
laboratory experiments, the rainfalls can only be obtained with rainfall simulators.
The uses of rainfall simulators have a long history in both laboratory and field
investigations. With rainfall simulators, the United States and the Soviet Union began
to model and monitor the processes of soil and water losses as early as the 1930s.
China began to design and manufacture rainfall simulators in the 1960s. However,
the technology has been developing rapidly in recent decades, and China has been
at the forefront of designing and applying rainfall simulators.
To ensure the similarity between rainfall simulations is very important in the
study of soil erosion. Nevertheless, differences may exist in raindrop characteristics
between simulated rainfalls and natural events, such as raindrop size, velocity, and
© Science Press and Springer Nature Singapore Pte Ltd. 2020
X. Xu et al., Experimental Erosion,
https://doi.org/10.1007/978-981-15-3801-8_3
29
A Conventional Experimental Technique:
Rainfall Simulation
Abstract Rainfall simulation is widely used for the experimental study on soil
and water conservation. This chapter reviews the characteristics, application, and
prospect of rainfall simulator. The rainfall simulators could be divided into two main
groups: the non-pressurized rainfall simulators, including the thread droppers and the
needle droppers, and the pressurized water rainfall simulators, including the spout
and the sprayer. The former could be hardly found at present due to its drawback that
the minimum size of drop produced is far larger and more even than most natural
rainfall and the simulator could not easily generate rains with the similar energy to
the natural one. Rainfall simulation halls with automatic operation and observation
systems are booming in recent years, but the basic simulators will not be completely
replaced in virtue of the cheap price and convenient manipulations.
Keywords Rainfall simulator · Soil erosion · Research advance
3.1 Methods for Simulating the Rainfall
Rainfall is one of the major factors causing hydraulic erosions. However, natural
rainfall experiments might require a considerable amount of time to complete. In
contrast, not only various rainfall intensities may be obtained, but also shorter durations may be permitted in experiments under simulated rainfalls. Moreover, it is
relatively easy to strictly control the experimental conditions and precisely monitor the processes of soil erosion in a rainfall simulation experiment. Especially for
laboratory experiments, the rainfalls can only be obtained with rainfall simulators.
The uses of rainfall simulators have a long history in both laboratory and field
investigations. With rainfall simulators, the United States and the Soviet Union began
to model and monitor the processes of soil and water losses as early as the 1930s.
China began to design and manufacture rainfall simulators in the 1960s. However,
the technology has been developing rapidly in recent decades, and China has been
at the forefront of designing and applying rainfall simulators.
To ensure the similarity between rainfall simulations is very important in the
study of soil erosion. Nevertheless, differences may exist in raindrop characteristics
between simulated rainfalls and natural events, such as raindrop size, velocity, and
© Science Press and Springer Nature Singapore Pte Ltd. 2020
X. Xu et al., Experimental Erosion,
https://doi.org/10.1007/978-981-15-3801-8_3
29