Turbulence reducing downhole apparatus

A method of controlling fluid flow in a string of tubing in drilling operations, comprising:

• providing a downhole valve apparatus having a tubular housing for connection within a bottom hole assembly in the string of tubing, when connected to an upper tubular housing of the string of tubing a top female end of the tubular housing receives a male end of the upper tubular housing in a joint region, the tubular housing including a valve bore of a first diameter communicating with a stress relief bore of a second diameter which is greater than the first diameter, the stress relief bore axially extending between a top opening of the valve bore of the tubular housing and a lower end of the joint region,
• wherein a float valve, including a valve member, is located within the valve bore of the tubular housing and partially within the stress relief bore, the float valve being axially movable relative to the tubular housing between a first configuration and a second configuration of the downhole valve apparatus;
• sealing an annular space between the float valve and the valve bore with at least one radial seal on the float valve;
• deploying the string of tubing including the downhole valve apparatus in a wellbore for a drilling operation and commencing the drilling operation;
• exposing the downhole valve apparatus to a first fluid, wherein the valve member allows a downward flow of the first fluid delivered to the stress relief bore, to flow through the float valve in the first configuration, wherein the downward flow of the first fluid to the stress relief bore axially moves the float valve downward within both the stress relief bore and the valve bore;
• and
• exposing the downhole valve apparatus to a second fluid, wherein the valve member blocks an upward flow of the second fluid toward the stress relief bore through the float valve in the second configuration and the upward flow of the second fluid axially moves the float valve upward within both the stress relief bore and the valve bore of the tubular housing,
• wherein sealing the annular space between the float valve and the valve bore prevents the second fluid from flowing into the stress relief bore through the annular space between the valve bore and the float valve in the second configuration.