This paper by Anatol Roshko presents experimental measurements of the flow around a large circular cylinder in a pressurized wind tunnel at Reynolds numbers ranging from \(10^6\) to \(10^7\). The study reveals a high Reynolds number transition where the drag coefficient increases from a low supercritical value to a constant value of 0.7 at \(R = 3.5 \times 10^6\), after which it remains constant. Additionally, vortex shedding occurs for \(R > 3.5 \times 10^6\) with a Strouhal number of 0.27. The experiments were conducted in the Southern California Co-operative Wind Tunnel (CWT) at pressures up to 4 atm, with the cylinder spanning the test section. The cylinder was a seamless steel pipe with a diameter of 18 inches and a surface roughness of about 200 μ-in. A hot-wire anemometer was used to measure the flow, and a splitter plate was installed to suppress vortex shedding. The results show that the drag coefficient \(C_d\) increases from about 0.3 to 0.7 in the range \(10^6 < R < 3.5 \times 10^6\), then levels off. The base pressure coefficient \(C_{pb}\) and Strouhal number \(S\) are also analyzed, showing that vortex shedding is not observed below \(R = 3.5 \times 10^6\). Roshko proposes a free-streamline model to describe the wake development, suggesting that the wake width decreases in the subcritical region and increases in the supercritical and transcritical regions. The model predicts a universal Strouhal number of 0.16, which is confirmed by the experimental data at transcritical Reynolds numbers. The presence of a splitter plate suppresses vortex shedding and slightly reduces the drag coefficient and base pressure coefficient. The upper transition to a new plateau regime is characterized by a turbulent separation point on the back of the cylinder, leading to a constant drag coefficient. The paper concludes with a discussion on the nature of the transitions and the asymptotic behavior of the flow as \(R \to \infty\), suggesting that further transitions are unlikely but that the flow in the wake may still be affected by increasing \(R\).This paper by Anatol Roshko presents experimental measurements of the flow around a large circular cylinder in a pressurized wind tunnel at Reynolds numbers ranging from \(10^6\) to \(10^7\). The study reveals a high Reynolds number transition where the drag coefficient increases from a low supercritical value to a constant value of 0.7 at \(R = 3.5 \times 10^6\), after which it remains constant. Additionally, vortex shedding occurs for \(R > 3.5 \times 10^6\) with a Strouhal number of 0.27. The experiments were conducted in the Southern California Co-operative Wind Tunnel (CWT) at pressures up to 4 atm, with the cylinder spanning the test section. The cylinder was a seamless steel pipe with a diameter of 18 inches and a surface roughness of about 200 μ-in. A hot-wire anemometer was used to measure the flow, and a splitter plate was installed to suppress vortex shedding. The results show that the drag coefficient \(C_d\) increases from about 0.3 to 0.7 in the range \(10^6 < R < 3.5 \times 10^6\), then levels off. The base pressure coefficient \(C_{pb}\) and Strouhal number \(S\) are also analyzed, showing that vortex shedding is not observed below \(R = 3.5 \times 10^6\). Roshko proposes a free-streamline model to describe the wake development, suggesting that the wake width decreases in the subcritical region and increases in the supercritical and transcritical regions. The model predicts a universal Strouhal number of 0.16, which is confirmed by the experimental data at transcritical Reynolds numbers. The presence of a splitter plate suppresses vortex shedding and slightly reduces the drag coefficient and base pressure coefficient. The upper transition to a new plateau regime is characterized by a turbulent separation point on the back of the cylinder, leading to a constant drag coefficient. The paper concludes with a discussion on the nature of the transitions and the asymptotic behavior of the flow as \(R \to \infty\), suggesting that further transitions are unlikely but that the flow in the wake may still be affected by increasing \(R\).