Lofting calculation formula for 90 degree shrimp elbow with high resolution

Lofting calculation formula for 90 degree shrimp elbow with high resolution

Cutting formula:
90 ° r = 1.5dn pushing elbow blanking length (mm) = elbow outer diameter (mm) * 1.5 * 1.57 * elbow outer diameter (mm) / pre selected steel pipe outer diameter (mm) + pre selected steel pipe wall thickness (mm) * 3
This formula also needs to refer to the manufacturer's core bar size

Dear predecessors, the calculation formula for the height of 30 degree 45 degree 60 degree 90 degree elbow
The height of elbow will not be calculated when setting out marine pipeline

Ring volume = 2x3.14x3.14 (R ^ 2) r r -- ring radius r -- ring radius of gyration R -- hollow pipe ring volume = 2x3.14x3.14 ((R ^ 2) - (R '^ 2)) r r' -- elbow (elbow) volume with inner ring radius of 90, 60 and 45 degrees is 1 / 4, 1 / 6 and 1 / 8 of corresponding hollow pipe ring volume respectively

The influence of Qinghai Tibet Plateau on China's climate and its causes
1. The influence of Qinghai Tibet Plateau on the climate of eastern China and its causes
2. The influence of Qinghai Tibet Plateau on the climate of Northwest China and its causes
3. The influence and reason of the increase of temperature and decrease of precipitation on the source of the three rivers in Qinghai Tibet Plateau

Your question is quite big. My general analysis of senior three students is as follows:
1、 Impact on air temperature
1. Mechanical blocking
The Qinghai Tibet Plateau, with a high altitude and a large area, stands between 29 ° D40 ° n, about 10 latitudes from north to South and 35 longitudes from east to west. It has a large area with an altitude of more than 5000m, and a series of peaks over 7000? D8000m, occupying the middle and low troposphere. It is like a huge island in the atmosphere and ocean, The cold wave invading China from western Siberia usually passes through Junggar basin, through Hexi Corridor and Loess Plateau, and then goes down to the eastern plain, As a result, the winter temperature in the tropical and subtropical regions of eastern China is much lower than that in the northern part of the Indian peninsula, which is protected by the Tibetan Plateau. In Table 6? 10, stations a, C and E are located in the northern part of the Indian peninsula, and their monthly average temperature in winter is respectively higher than that in stations B, D and F at the same latitude and height, especially in stations C and D. This is because station D Yuanling is located in the plain to the east of the plateau, The cold wave is unobstructed, and station C is located in the south of the plateau
In winter, the westerly flow is forced to branch when encountering the barrier of the Qinghai Tibet Plateau. It can be clearly seen from the monthly mean temperature map of 700hPa and 500hPa in the northern hemisphere in winter that in the northern part of the plateau, the northwest side is warmer than the northeast side in winter, while in the southern part of the plateau, the southeast side is warmer than the southwest side, Because the westerly wind branches in the west side of the plateau, there is warm advection in the northwest and cold advection in the southwest. After bypassing the plateau, the air converges, cold advection in the northeast and warm advection in the southeast
In summer, the Qinghai Tibet Plateau also has a certain blocking effect on the northward movement of the warm and humid air flow from the south, but the warm and humid air flow generally has an unstable stratification, which is easier to climb over mountains than the cold air, A part of the warm and humid air flows across the mountain pass or valley depression in the south of the plateau and flows into the south of the plateau, which is an important reason for the formation of the warm region of the Yarlung Zangbo River valley extending from east to west
According to the comparison of the average temperature of Quxian and Delhi at the same latitude in the last month, it can be seen that the temperature of Quxian is lower than that of Deli at 500hPa and below, especially in the winter half year
2. Thermal effect
Comparing the surface temperature of the Qinghai Tibet Plateau with that of the free atmosphere at the same altitude, the temperature of the plateau is lower in winter and higher in summer. According to the analysis and calculation of the observation data, the monthly heat transfer from the plateau atmosphere system to the surrounding atmosphere is shown in Table 6? 11. From November to February of the next year, the surrounding atmosphere provides heat to the plateau atmosphere system, and the Qinghai Tibet Plateau is a cold source, In spring and summer, the Qinghai Tibet Plateau is a strong heat source, and its intensity is the largest in June and July, providing heat to the surrounding atmosphere for more than 850j / cm2d, In the whole troposphere, the temperature of the plateau is higher than that of the surrounding area, and then extends to the upper warm zone, and reaches the 100hPa layer, the temperature distribution appears warm in high latitude and cold in low latitude
From the surface temperature of the Qinghai Tibet Plateau, it has the following characteristics
(1) The third pole of the earth: the Qinghai Tibet Plateau is located in the subtropical and warm temperate latitudes due to its high altitude and low temperature. However, in the northern part of the main body of the plateau, the Qilian Mountains and the eastern part of Bayan Har, the average surface temperature in January appears a closed isotherm of - 16? D-18 ℃. In the midsummer, there is still a large area with average temperature less than 8 ℃ in July, and the average temperature in winter and summer is 18? D20 ℃ lower than that in the eastern plain of the same latitude
(2) Diurnal and annual temperature range: the diurnal temperature range of the Qinghai Tibet Plateau is larger than that of the eastern plain and Sichuan Basin at the same latitude, larger than that of the free atmosphere at the same altitude, and the annual temperature range is also larger than that of the free atmosphere at the same altitude, but slightly smaller than that of the eastern plain at the same latitude due to its high altitude
(3) The seasonal temperature changes rapidly, and the spring temperature is higher than the autumn temperature: the Tibetan Plateau has a strong warming intensity in spring, especially after snow melting, and before the rainy season, because of the strong solar radiation, the plateau has a very fast warming and a fast cooling rate in autumn, and the spring temperature is higher than the autumn temperature. For example, the temperature difference between April and October in Bangor is 2.8 ℃, while that in Hankou is - 1.4 ℃
All of these indicate that the plateau temperature has the characteristics of continental climate
2、 Plateau monsoon
In the Qinghai Tibet Plateau, due to its thermal difference with the surrounding free atmosphere, the prevailing wind system opposite to winter and summer is called plateau monsoon. In winter, cold high pressure appears on the plateau, while thermal low pressure appears in winter. Its horizontal range is large in the lower layer and small in the upper layer, and its thickness is larger in summer than in winter. The seasonal variation of wind is generally the earliest in the north of the plateau, the last in the plateau, the second in the east of the plateau, and the latest in the south of the plateau
The plateau monsoon has a great influence on circulation and climate. Firstly, it increases the thickness of the lower troposphere monsoon in winter and summer in China. The southwest of China is located in the southeast of the cold high circulation and the hot low circulation of the Qinghai Tibet Plateau in winter and summer respectively. The northeast monsoon and the southwest monsoon should prevail respectively, which are completely consistent with the direction of the lower troposphere monsoon formed by the thermal difference between the sea and the land, Therefore, the thickness of monsoon in Southwest China is particularly large
The greater influence of the plateau monsoon is that it destroys the planetary pressure belt and planetary circulation in the middle troposphere. Due to the strong cold high in winter and hot low in summer, the thickness of the plateau can reach 5km in winter and 5? D7km in summer. Therefore, from the sea level to the height of 5? D7km, the air in winter diverges from the plateau and converges to the plateau in summer, In winter, the circulation is similar to that of Hadley circulation. In summer, the circulation is opposite to that of Hadley circulation. The air rises in the plateau, flows to low latitudes at high altitude, sinks, and turns to higher latitudes after reaching the ground, which also plays a great role in the adjustment of air quality between the northern and southern hemispheres
3、 Impact on precipitation
1、 Impact on surrounding areas
The Qinghai Tibet Plateau has a wide influence on the distribution of precipitation in Asia. According to the latest climate model, if there is no Qinghai Tibet Plateau, the southwest monsoon in summer can only reach the south of the Indian Ocean. Most parts of China are westerly and northwesterly, controlled by the downdraft. Therefore, the continent will have a dry climate with little water vapor, even in India and Myanmar, The influence of the existence of the Qinghai Tibet Plateau on the large-scale airflow first induces the tropical southwest monsoon to invade India and Myanmar, resulting in the plateau rainy season. At the same time, a part of the southwest monsoon goes deep into the east of China and forms the Jiangnan rainy area. Without the Qinghai Tibet Plateau, the drought in the west of China will be more serious, Before the uplift of the Qinghai Tibet Plateau, about tens of millions of years ago, there was a broad arid climate belt from the north of China to the Yangtze River Basin
2、 Precipitation distribution of the plateau itself
In summer, on the southern slope of the Tibetan Plateau, just as the windward slope of the southwest monsoon from the Indian Ocean, the precipitation is very abundant. The most famous example is kilapenzi, where the annual average precipitation is more than 11000 mm, and the maximum annual precipitation is 26461.2 mm, of which the precipitation in July is 9300 mm, For example, Dingri, which is located at the northern foot of the main peak of the Himalayas, has an altitude of 4300m and an annual precipitation of 318.5mm