In the far northwest, desert and snow are constantly intertwined. Under the blowing of the wind, these two tiny particles on the surface can cause great changes, thus forming natural disasters such as sandstorms and snowstorms, causing great trouble to people's lives and threatening people's travel safety.
Huang Ning, a professor at the School of Civil Engineering and Mechanics of Lanzhou University, started from fluid mechanics to study the movement of particles under the action of wind, and explored effective methods to prevent and eliminate sandstorms and snow storms. Through field observation, experimental analysis, etc., he found that the movement of particles is closely related to the speed, direction and topography of the wind, and that the force of the wind can be effectively reduced by changing the arrangement and structure of the particles.
Huang Ning (left) inspects the desert. Photo courtesy of the interviewee.
Start in the west, starting with the sand.
In 1984, Huang Ning chose to major in mechanics and started the exploration of applying what he had learned. This choice stemmed from a quote from the then head of the department: "Mathematics can be applied as a tool to other disciplines for the better benefit of humanity." ”
However, the real challenge has only just begun.
In 1997, the young Huang Ning stood at the crossroads of his life, with a thirst for knowledge and a vision for the future, ready to step into the door of doctoral research. That year, he received the research project of his mentor Zheng Xiaojing (elected as an academician of the Chinese Academy of Sciences in 2009) - the phenomenon of wind-sand two-phase flow. This is one of the most challenging problems in the international academic community, and it is also a major national need.
The phenomenon of wind, sand and electricity is full of mystery and unknown. In aeolian sandstorms, sand particles collide and rub against each other to produce static electricity, forming a unique phenomenon of aeolian sandstorms. This seemingly insignificant phenomenon has a profound impact on the entire wind-blown sand movement. For this topic, Huang Ning felt not only a challenge, but also a call to duty.
In the 90s of the last century, northern China faced serious sandstorm hazards, and there was still a blank in China for the research on sandstorm winds and sandstorms. Huang Ning said that as a native of Northwestern, he wanted to do something for his hometown.
Huang Ning knows that this topic is very cutting-edge and urgent. Sand and dust storm disasters are an urgent problem to be solved in environmental disasters, and the world is looking for solutions. Uncovering the mystery of the phenomenon of wind and sand electricity may be the key to eliminating the disaster of sand and dust storms.
In order to gain an in-depth understanding of the sand activities in various places, Huang Ning led the team to set up observation points in Dunhuang, Jinta, Jinchang and other places in Gansu Province, and carried out fixed-point observations for a long time. At the same time, they also used numerical simulation technology to simulate the movement process of wind and sand, in order to better understand its causes and characteristics.
On the road of scientific research, they often encounter dangers. Once, while they were making a routine observation, the sky suddenly darkened and the wind suddenly increased. This is a sign of a black storm coming. The Black Storm is an extreme weather phenomenon in the desert that is powerful enough to engulf an entire research team. Huang Ning knew that at this time, the contact with the outside world had been cut off, and they were trapped in the depths of the desert.
Faced with such danger, Huang Ning did not panic. He quickly organized the team and took a series of emergency measures to protect personal safety and prevent damage to the instrument caused by sandstorms. At the same time, they keep a close eye on the storm and look for the best escape route.
Over the next few hours, Huang Ning and his team engaged in a life-and-death battle against Black Storm. The Black Storm was more powerful than they could have imagined, the entire sky was covered in sand and dust, and visibility was almost zero. Eventually, after a long and difficult wait, the storm finally subsided, and Huang Ning and his team members managed to avoid the disaster with courage and wisdom. This experience made Huang Ning more aware of the power of the desert and made him more in awe of nature.
Day after day, year after year, Huang Ning and his team gradually figured out the characteristics and causes of the wind and sand movements, as well as the differences between different regions.
After more than 20 years of efforts, he put forward a comprehensive treatment plan according to local conditions from the perspectives of wind prevention, sand blocking, and sand fixation, combined with the basic theory of wind and sand movement, combined the commonality and characteristics, and achieved important research results in the field of wind and sand two-phase flow, which provided an important scientific basis for understanding this complex phenomenon, promoted the research in the field of wind and sand environmental mechanics in China, and enhanced China's international influence in this field. In 2018, Huang Ning, together with his mentor Zhou Youhe (elected as an academician of the Chinese Academy of Sciences in 2021) and Zheng Xiaojing, won the second prize of the National Natural Science Award.
Putting what you have learned into practice starts with the railway.
The western section of the Lanxin Railway is 123 kilometers long, and this section is blowing more than 8 strong winds for more than 300 days a year, and the 12 winds are blowing when they are blowing, which is called the "100-mile wind area".
Here, strong winds carry sand and dust, and severe wind erosion of railway facilities such as roadbeds, bridges and culverts. Window panes are shattered, paint is worn away, goods are blown away, and even trains derail. Railway workers in the wind area are battling the wind and sand every day to ensure the normal operation of the railway.
Huang Ning was commissioned to design a wind barrier for the Lanxin Railway, and after repeated research and experiments, a solid retaining wall was finally designed at the wind direction of the railway. This retaining wall is based on the premise of low cost, which avoids the danger of overturning the train due to strong crosswinds to the greatest extent, and plays a very good protective effect.
However, 10 years later, new problems arose. Although the wind barrier blocks strong winds, it exacerbates the problem of sand accumulation in the area of the railroad tracks that it protects. In the face of new challenges, Huang Ning once again carried out in-depth research, clarified the causes and mechanisms of aggravation of sedimentation, and gave solutions.
The success of the Lanxin railway windshield test made him associated with railway protection for the second time.
Along the southern edge of the Taklamakan Desert, the second largest mobile desert in the world, the railway runs from west to east, about 3 4 sections of the railway are in the desert. This is the world's first circum-desert railway, and the wind and sand are seriously harmful to the construction and operation of the railway.
Here, Huang Ning and his team braved the scorching sun and sandstorms, and after countless tests and corrections, they successfully developed a calculation model and program for railway sand movement suitable for the desert surface in the region, providing a scientific basis for sand prevention and control projects.
He found that factors such as wind direction, particle size and distribution of sand particles all affect the trajectory of wind sand. On this basis, Huang Ning proposed an optimal design plan for sand prevention and control, suggesting the use of specific vegetation, the construction of wind walls and drainage systems, etc., to reduce the impact of sand on the railway. These solutions not only improve the safety of the railway, but also provide a useful reference for the local ecological and environmental protection.
Due to Huang Ning's academic article on wind and sand, the editor of the Discovery Channel contacted Huang Ning and asked him to give an exclusive interview. In this regard, Huang Ning gladly accepted. He hopes that this will help more people around the world understand the value of sandstorm research and the importance of environmental protection.
Desert is a typical type of landform in nature. We are curious about this area because there are so many unknowns about it, and this is what drives our work. Huang Ning said.
Explore the unknown and set off to Mars.
The snow cover of the Qilian Mountains, a pearl in western China, is the main freshwater resource in the Hexi Corridor, and is not only related to the lives of the local population, but also to the ecological balance of the whole of Asia. With the intensification of global climate change, the snow cover in the Qilian Mountains has attracted much attention.
In recent years, Huang Ning has gradually shifted the focus of his research from wind-blown sand to snow cover, and has deeply studied the distribution and change of snow cover in the Qilian Mountains through remote sensing monitoring and field investigations.
Shuttling between the mountains and trekking on the vast snowfields, Huang Ning's team collected a large number of data and samples, and revealed the distribution law and evolution mechanism of snow water resources in these alpine mountains, which not only laid a theoretical foundation for the scientific assessment of water resources in these areas, but also provided technical support for ecological protection.
In the next step, Huang Ning has expanded his research horizon to distant Mars, which stems from the mysterious connection between Earth and Martian dust.
Martian dust storms are large and persistent, posing a serious threat to exploration missions. He knows that understanding the causes and movements of these dusts and their effects on the climate and geology of Mars will be crucial for future Mars exploration missions.
Dust storms are a common phenomenon on Mars that can cover the entire planet's surface, affecting solar radiation absorption and temperature distribution in the planet's atmosphere. These dust storms are different from those on Earth in that they are larger and last longer, and can last for months. "Due to the high hardness of Martian dust particles, they can cause severe wear and tear on the surface of the probe during high-speed movement." ”
Huang Ning's team, in collaboration with the State Key Laboratory of Lunar and Planetary Sciences of Macau University of Science and Technology, analyzed the wear of dust particles of different particle sizes and speeds on the surface of the probe through experimental observation and numerical simulation, and put forward protective suggestions such as regular cleaning of lenses and the use of dustproof coatings. In addition, in order to improve the anti-clogging performance and life of mechanical parts, they put forward suggestions for optimizing the mechanical structure of related instruments and using dust-proof materials.
Scientific research is not an easy road, but I always enjoy it, and on the road of exploring the unknown, all difficulties are insignificant compared to the joy of reaping the results. From Earth to Mars, I will continue my journey in the dust, and my pursuit of scientific truth will never stop. Huang Ning said.