e-mosty September 2017: Mersey Gateway Bridge. Arenales Bridge. Mersey Gateway Bridge. Arenales Bridge. BLWT. - Page 40

Front operation sector provides steady wind flow up to a velocity of 32 m/s (115 km/h). The sector will be used for testing of sectional models of thin structures and their parts see Fig. 6 - 10 (bridges, masts, chimneys, towers, hinges and bridge cables, etc.) where the wind effects are dominant. The results provide data about mean and dynamic loads and response of structures to the wind effects. The front section was tested for the flow uniformity. Using digital probe ALMEMO detailed measurements of the horizontal profiles of wind speed were made in the front section. Barometric pressure: p b = 98 770 [Pa], temperature: T = 18.3 – 18.6 [°C], air density: ρ = 1.17548 – 1.1742 [kg/m 3 ], U - mean wind speed, Ur - reference wind speed on Prandtl sensor. Measurements were made from the base height of 800 mm ± z above the floor. Preliminary tests reported that measured mean wind velocity at this section differed less than 1% and vertical tunnel walls affect uniformly distributed wind flow to a distance 400 - 450 mm from the walls (see Fig. 5). ← Figure 4: Front operation sector FRONT OPERATION SECTION - STEADY WIND FLOW 1,2 1 0,8 z = 500 [mm] U/Ur z = 200 [mm] z = - 200 [mm] z = - 500 [mm] 0,6 0,4 0,2 ← Figure 5: Steady wind flow at different heights in the front cross section 0 -1500 -1000 -500 0 500 1000 1500 y [mm] Figures 6 + 7: View on sectional model in front sector in steady wind flow - cylinder 3/2017