Venturi Effect The Venturi effect is named after an Italian Physicist; Giovanni Venturi (1746–1822). The Venturi Effect is the reduction in fluid pressure that results when the airflows through a constricted section (or choke) in the wind tunnel test section. The reduction in fluid pressure causes the airflow velocity in the restricted area to increase.

Venturi Effect Air Flow Air Flow ©2016, GDJ Inc.

Continuity Equation 𝑽 𝟏 ∗ 𝑨 𝟏 = 𝑽 𝟐 ∗ 𝑨 𝟐 After obtaining data, the next step is to be able to calculate the velocity and area at different points in the venturi with the obtained data. We can apply the Continuity Equation to calculate Velocity or area at different points in the Venturi tube 𝑽 𝟏 ∗ 𝑨 𝟏 = 𝑽 𝟐 ∗ 𝑨 𝟐 V1= Velocity at the first point A1 = Area at the first point V2 = Velocity at the second point A2 = Area at the second point

Continuity Equation 𝑨=𝑳∗𝑾 To calculate the Area of the test section, use the formula: 𝑨=𝑳∗𝑾 A = Area of the test section L = Height of the test section W = Width of the test section The Area then can be used in the continuity equation to find other variables in the equation

Flotek 360 Wind Tunnel with two, five degree Venturi shapes installed.

Continuity Equation = ∗ A 3.5" 6" 𝟐𝟏𝒊 𝒏 𝟐 = ∗ A 4.7" 6" 𝟐𝟖.𝟐𝒊 𝒏 𝟐 Pressure Taps 5 4 3 2 1 = ∗ A 3.5" 6" 𝟐𝟏𝒊 𝒏 𝟐 𝐻 2 =4.7" 𝐻 1 =3.5" Airflow = ∗ A 4.7" 6" 𝑊𝑖𝑑𝑡ℎ=6” 𝟐𝟖.𝟐𝒊 𝒏 𝟐

Continuity Equation 𝐴 1 𝑉 1 = 𝐴 2 𝑉 2 𝐴 1 𝑉 1 = 𝐴 2 𝐴 2 𝐴 2 𝑉 2 𝑉 2 Pressure Taps 𝐴 1 𝑉 1 = 𝐴 2 𝑉 2 𝐴 1 𝑉 1 = 𝐴 2 𝐴 2 𝐴 2 𝑉 2 5 4 3 2 1 𝐻 2 =4.7" 𝐻 1 =3.5" Airflow 𝑉 2 𝑊𝑖𝑑𝑡ℎ=6”

Continuity Equation 𝑉 1 ∗ 𝐴 1 𝑉 2 = 𝐴 2 ∗ 𝑉 2 = 𝑽 𝟐 = 50𝑓𝑝𝑠 21𝑖 𝑛 2 Pressure Taps 𝑉 1 ∗ 𝐴 1 𝑉 2 = 5 4 3 2 1 𝐴 2 𝐻 2 =4.7" 𝐻 1 =3.5" Airflow ∗ 50𝑓𝑝𝑠 21𝑖 𝑛 2 𝑉 2 = 28.2𝑖 𝑛 2 𝑊𝑖𝑑𝑡ℎ=6” 𝑽 𝟐 = 37.2fps

Continuity Equation

Continuity Equation 𝐴 1 𝑉 1 = 𝐴 2 𝑉 2 𝐴 1 𝑉 1 = 𝐴 2 𝐴 2 𝐴 2 𝑉 2 𝑉 2 𝐴 1 𝑉 1 = 𝐴 2 𝑉 2 𝐴 1 𝑉 1 = 𝐴 2 𝐴 2 𝐴 2 𝑉 2 𝑉 2 𝑉 2 𝑉 2 𝐴 2 𝑉 2 𝑉 2