Ruído do vento

501-25-82 Body Repairs - General Information 501-25-82 DESCRIPTION AND OPERATION roof, doors and side windows. When the vehicle is moving fast, air layers (turbulence) form, which cause variations in air pressure. These variations in air pressure spread in the form of sound waves and are transferred to the vehicle interior via the side windows and seals. Noises caused by deviations in air flow and circulation around separate components: If air flows over an edge on a vehicle, the air flow cannot follow the shape of the surface, but separates at the edge. Eddies are formed, which collapse again after a certain time or distance. The associated fluctuations in air pressure create a corresponding sound wave which is noticeable by for instance a rushing noise at the A-pillar or the outside mirror. Turbulence and the associated radiation of noise can also occur at the vehicle underbody. Air circulation around small components and also flow through small gaps (e.g. the radiator grille) cause the rushing noise to change to a whistling, which rises and becomes louder as the vehicle speed increases. Noises caused by vibrating seals: Seals which do not make firm contact at the door or window area can be made to vibrate by pressure variations outside the vehicle, which in turn mean noise radiating into the interior of the vehicle. Noises caused by air flowing out: Noises caused by air flowing out are created by leaks at the vehicle interior sealing system, when stationary air mixes with flowing air. As a result, the noise increases as the speed of the air flowing out increases. Example: Letting air out of a tire. Cavity noises: Cavity noises are those created when the air volumes found in bodywork cavities are caused to vibrate by an opening located in the airflow. The frequency of the tone does not vary with the vehicle speed but depends on the volume of the cavity and the size of the opening. Example: Blowing across the top of a bottle. Wind noises overview: Workshop diagnosis Assessm Type of wind Place of origin HQW noises Normal "Normal" wind Roof, side noises windows Normal Noises caused A-pillars, outside partly by mirrors, changes in the antennas direction of air flow and by air flow around separate components Serious Noises caused Door gaps too by vibrating large, door/ seals window seals not making firm contact Serious Air escape and Leaks in the air passage bodywork/ noises sealing system Serious Cavity noises Unsealed body- work cavities Those noises listed under "Serious" indicate a possible source of the fault. Workshop diagnosis There are two ways that the level of noise in the vehicle interior can be reduced and the character of the noise can be improved through assessment and diagnosis in the service department: ‡ Reducing the intensity of the noise sources. ‡ Reducing the noise transfer routes. Before carrying out repair work, a visual inspection of the vehicle must be carried out. The gaps in the doors, the sunroof and at all other body parts must be checked in particular. When the doors are adjusted to fit exactly, development of wind noises at high speeds can often be eliminated (lifting of doors off the seals). Furthermore, the following points should be noted: ‡ The windows and doors must be fully closed. ‡ The air guides and air grilles must be correctly seated. ‡ All of the trim strips and plastic components must be firmly fixed down without gaps. ‡ All blanking plugs present.