ÖZETBu araştırma, 30 başlık kapalı ve duraklı süt sığırı ahırının 1/20 ölçeklimodeli üzerinde yapılmıştır. Rüzgar hızı ve yönü ile farklı 4 tipte planlanan mahya havaçıkış açıklıklarının model içi hava dağılımına ve havalandırma miktarına olan etkisiaraştırılmıştır. Araştırma laboratuvar koşullarında yapılmış olup rüzgar tünelinden sağlanandeğişik yönlerden esen farklı rüzgar hızları ile mahya hava akım hızlan ve model içi ve dışıarasındaki sıcaklık farklarıyla olan ilişkileri belirlenmiştir.Araştırmadan elde edilen sonuçlara göre, mahya açıklığının şekli, rüzgar yönü veyapının konumu mahya hava akım hızını önemli ölçüde etkilemektedir. Dikdörtgen orifısşeklinde planlanan mahya açıklık tipi, diğer tiplere oranla daha uygun havalandırmasağlamaktadır.RIDGE VENT, WIND DIREKTION AND WIND VELOCITY EFFECTSON CLOSED, NATURALLY VENTTLATED, CATTLE BUILDlNG VENTILATIONSUMMARYNaturally ventilated buildings used for cattle production havavarious ridge vent configurations. Information pertaining to the ventilation characteristicsofdifferent geometrically shaped ridge vent is limited. Therefore, the effects ofwind speed,wind direction and ridge vent shape were studied in a model (1/20 scale) on ventilationcharacteristics, naturally ventilated, dairy cattle building. A simple wind tunnel was built todevelop an airflow pattern. Wind was simulated by variable speedfans. Wind speed variedbetween 0 to 7 mJs.The construction of the model was based on a geometric lenght scale of 20, and theassumption was t hat the samefluid and material would be used in the model and prototype, Trusses, purlins, poles, sides and roof were made of wood. The end walls wereconstructed with plexiglass for the purpose ofvisual observation of airflow patterns. Thefour ridge vents were constructed by using galvanized metal.Principles of similitude and dimensional analysis were utilized in deriving a set ofindependent and dependent Pi terms, From the defination of the Buckingham Pi Theorem aset of14 dimensionless Pi terms were obtained (Langhaar, 1983).The sdudy descr 'ıbed in this paper was conducted to determine which type of ridgevent would be suitable for naturally ventilated dairy barns in cold regions. Resuîts indicatedthat ridge vent design has a signifıcant effect on outled velocity and wind velocity.Temperature difference was affected by ridge vent geometry and vind velocity.The baffled (Type II) ridge vent had the highest outlet velocity when ali winddirections were considered, while covered (Type III) ridge vend produced the lowest outletvelodties.AUhough the covered ridge vent produced the largest temperature differences, theassociated low outlet velodties make it the least desirable of the four ridge vents tested.