第三篇结构抗风Part 3 Wind-resistant structure第八章大气边界层的平均风特性Chapter 8 characteristics of mean wind in the atmospheric boundarylayer第九章平均风的概率计算Chapter9Probabilisticcalculationofmeanwind第十章脉动风的概率特性Chapter 10Probabilistic characteristics of fluctuating wind第11章结构顺风向随机风振响应Chapter11Structural downwinddynamicresponse第十二章风振控制Chapter 12 Wind vibration control
第三篇 结构抗风 Part 3 Wind-resistant structure 第八章 大气边界层的平均风特性 Chapter 8 characteristics of mean wind in the atmospheric boundary layer 第九章 平均风的概率计算 Chapter 9 Probabilistic calculation of mean wind 第十章 脉动风的概率特性 Chapter 10 Probabilistic characteristics of fluctuating wind 第11章 结构顺风向随机风振响应 Chapter 11 Structural downwind dynamic response 第十二章 风振控制 Chapter 12 Wind vibration control
Introduction一、风的概念Conceptofwind空气从气压大的地方向气压小的地方流动而形成风，风是空气的水平运动Wind is caused by the movement of air from the higher to thelower pressure areas.Wind is thehorizontal movementofair.赤道和低纬度地区：受热量较多，气温高，空气密度小、气压小，且大气因加热膨胀，由地表向高空上升Atequatorandlowlatitudes:moreheatandhighertemperaturecausetheatmosphereexpanding,lowerdensityandpressurerisingfromthesurfaceintosky极地和高纬度地区：受热量较少，气温低，空气密度大、气压大，且大气因冷却收缩由高空向地表下降+Arcticandhighlatitudes:Lessheatandlowertemperaturecausetheatmosphere shrinking,higherdensityandpressuredropping to the surface from sky
一、风的概念 Concept of wind 空气从气压大的地方向气压小的地方流动而形成风，风是空气的水平 运动 Wind is caused by the movement of air from the higher to the lower pressure areas. Wind is the horizontal movement of air. Introduction 赤道和低纬度地区：受热量较多，气温高，空气密度小、气压小,且大 气因加热膨胀，由地表向高空上升 At equator and low latitudes: more heat and higher temperature cause the atmosphere expanding, lower density and pressure, rising from the surface into sky 极地和高纬度地区：受热量较少，气温低，空气密度大、气压大，且 大气因冷却收缩由高空向地表下降 Arctic and high latitudes: Less heat and lower temperature cause the atmosphere shrinking, higher density and pressure, dropping to the surface from sky
Introduction风的两个基本要素：风向和风速，由风向标和风速仪测量Twobasicelementsdescribedwind:directionandspeedmeasuredbyVaneandanemometer北风（8-12级）西北东北风（6级）西东风（7级）东南西南Wind Cup南原理：利用风杯在风作用下的旋转速度来测量风速Principle:Measuringwind speedbytherotational speed ofthewindcupunderwind
风的两个基本要素：风向和风速，由风向标和风速仪测量 Two basic elements described wind: direction and speed, measured by Vane and anemometer Introduction Wind Cup 原理：利用风杯在风作用下的旋转速度来测量风速。 Principle: Measuring wind speed by the rotational speed of the wind cup under wind
风速常用风级表示风速WindSpeedWind speed is usually described byBeaufort windforce scale风级浪高（米）名称风速(米/秒)陆地物象海面波浪WaveBeaufortDescriptionLand conditionsSpeed(m/s)Sea conditionsheight(m)number烟直上平静无风00.00.0-0.2Smoke risesCalmmildvertically.微波峰无飞沫烟示风向Rippleswiththe软风Smoke drift10.10.3-1.5appearanceofscalesindicates windLight airare formed,butdirectionwithoutfoamcrests轻风感觉有风小波峰未破碎21.6-3.30.2LightWind felt onSmall wavelets.breezeexposed skincrestsdonot break小波峰顶破裂微风旗展开Large wavelets.30.6Gentle3.4-5.4lightflagsCrests begin tobreezeextendedbreak
风速常用风级表示 Wind speed is usually described by Beaufort wind force scale 风级 Beaufort number 名称 Description 风速(米/秒) Speed(m/s) 陆地物象 Land conditions 海面波浪 Sea conditions 浪高（米） Wave height(m) 0 无风 Calm 0.0-0.2 烟直上 Smoke rises vertically. 平静 mild 0.0 1 软风 Light air 0.3-1.5 烟示风向 Smoke drift indicates wind direction 微波峰无飞沫 Ripples with the appearance of scales are formed, but without foam crests 0.1 2 轻风 Light breeze 1.6-3.3 感觉有风 Wind felt on exposed skin 小波峰未破碎 Small wavelets. crests do not break 0.2 3 微风 Gentle breeze 3.4-5.4 旌旗展开 light flags extended 小波峰顶破裂 Large wavelets. Crests begin to break 0.6
风速WindSpeed风级名称浪高（米）陆地物象海面波浪风速（米）*DescriptiWaveBeaufortSpeed(m)Land conditionsSea conditionsheight(m)onnumber小浪白沫波峰和风吹起尘土Small waveswith1.04Moderat5.5-7.9Dustandloosebreaking crests.e breezeFairly frequentpaper raisedwhitecaps小树摇摆中浪折沫峰群劲风Small trees inModerate waves of52.0Fresh8.0-10.7leaf begin tosomelength.Manybreezewhitecaps.sway大浪到个飞沫电线有声强风Long waves beginWhistling heard63.010.8-13.8Strongto form.Whitein overheadfoam crests arebreezewiresvery frequent
风级 Beaufort number 名称 Descripti on 风速（米）* Speed(m) 陆地物象 Land conditions 海面波浪 Sea conditions 浪高（米） Wave height(m) 4 和风 Moderat e breeze 5.5-7.9 吹起尘土 Dust and loose paper raised. 小浪白沫波峰 Small waves with breaking crests. Fairly frequent whitecaps. 1.0 5 劲风 Fresh breeze 8.0-10.7 小树摇摆 Small trees in leaf begin to sway 中浪折沫峰群 Moderate waves of some length. Many whitecaps. 2.0 6 强风 Strong breeze 10.8-13.8 电线有声 Whistling heard in overhead wires 大浪到个飞沫 Long waves begin to form. White foam crests are very frequent. 3.0